chore: release v0.3.0-alpha.2 (#898)

## 🤖 New release
* `hugr`: 0.3.0-alpha.1 -> 0.3.0-alpha.2 (⚠️ API breaking changes)

### ⚠️ `hugr` breaking changes

```
--- failure enum_missing: pub enum removed or renamed ---

Description:
A publicly-visible enum cannot be imported by its prior path. A `pub use` may have been removed, or the enum itself may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.30.0/src/lints/enum_missing.ron

Failed in:
  enum hugr::ops::custom::ExternalOp, previously in file /tmp/.tmpZslYkR/hugr/src/ops/custom.rs:20
  enum hugr::ops::leaf::LeafOp, previously in file /tmp/.tmpZslYkR/hugr/src/ops/leaf.rs:21
  enum hugr::ops::LeafOp, previously in file /tmp/.tmpZslYkR/hugr/src/ops/leaf.rs:21

--- failure enum_variant_added: enum variant added on exhaustive enum ---

Description:
A publicly-visible enum without #[non_exhaustive] has a new variant.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#enum-variant-new
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.30.0/src/lints/enum_variant_added.ron

Failed in:
  variant ConstTypeError:NotMonomorphicFunction in /tmp/.tmpoZAGEw/hugr/hugr/src/ops/constant.rs:98
  variant ConstTypeError:NotMonomorphicFunction in /tmp/.tmpoZAGEw/hugr/hugr/src/ops/constant.rs:98
  variant SignatureError:CallIncorrectlyAppliesType in /tmp/.tmpoZAGEw/hugr/hugr/src/extension.rs:172

--- failure enum_variant_missing: pub enum variant removed or renamed ---

Description:
A publicly-visible enum has at least one variant that is no longer available under its prior name. It may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.30.0/src/lints/enum_variant_missing.ron

Failed in:
  variant InterGraphEdgeError::InvalidConstSrc, previously in file /tmp/.tmpZslYkR/hugr/src/hugr/validate.rs:774
  variant OpType::LeafOp, previously in file /tmp/.tmpZslYkR/hugr/src/ops.rs:30
  variant SignatureError::TypeApplyIncorrectCache, previously in file /tmp/.tmpZslYkR/hugr/src/extension.rs:171
  variant EdgeKind::Static, previously in file /tmp/.tmpZslYkR/hugr/src/types.rs:44
  variant ConstTypeError::FunctionTypeMissing, previously in file /tmp/.tmpZslYkR/hugr/src/ops/constant.rs:99
  variant ConstTypeError::FunctionTypeMissing, previously in file /tmp/.tmpZslYkR/hugr/src/ops/constant.rs:99

--- failure inherent_method_missing: pub method removed or renamed ---

Description:
A publicly-visible method or associated fn is no longer available under its prior name. It may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.30.0/src/lints/inherent_method_missing.ron

Failed in:
  OpType::as_leaf_op, previously in file /tmp/.tmpZslYkR/hugr/src/ops.rs:103
  OpType::is_leaf_op, previously in file /tmp/.tmpZslYkR/hugr/src/ops.rs:103

--- failure method_parameter_count_changed: pub method parameter count changed ---

Description:
A publicly-visible method now takes a different number of parameters.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#fn-change-arity
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.30.0/src/lints/method_parameter_count_changed.ron

Failed in:
  hugr::types::PolyFuncType::validate now takes 2 parameters instead of 3, in /tmp/.tmpoZAGEw/hugr/hugr/src/types/poly_func.rs:76

--- failure struct_missing: pub struct removed or renamed ---

Description:
A publicly-visible struct cannot be imported by its prior path. A `pub use` may have been removed, or the struct itself may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.30.0/src/lints/struct_missing.ron

Failed in:
  struct hugr::ops::leaf::TypeApplication, previously in file /tmp/.tmpZslYkR/hugr/src/ops/leaf.rs:82
```

<details><summary><i><b>Changelog</b></i></summary><p>

<blockquote>

## 0.3.0-alpha.2 (2024-04-15)

### Documentation

- Specify direct children in `HugrView::children`
([#921](#921))
- Add logo svg to readme and spec
([#925](#925))

### Features

- [**breaking**] No polymorphic closures
([#906](#906))
- [**breaking**] Flatten `LeafOp`
([#922](#922))

### Refactor

- Combine ExtensionSolutions (no separate closure)
([#884](#884))
- [**breaking**] Merge `CustomOp` and `ExternalOp`.
([#923](#923))
</blockquote>


</p></details>

---
This PR was generated with
[release-plz](https://github.com/MarcoIeni/release-plz/).

---------

Signed-off-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Agustin Borgna <agustin.borgna@quantinuum.com>

hugr/CHANGELOG.md

@@ -1,8 +1,17 @@
 # Changelog
 
-## Unreleased (xxxx-xx-xx)
+## 0.3.0 (2024-04-15)
 
-This release includes multiple breaking changes to the API, including the rename of the crate from `quantinuum_hugr` to `hugr`.
+### Main changes
+
+This release includes a long list of breaking changes to the API.
+
+- The crate was renamed from `quantinuum_hugr` to `hugr`.
+- The API has been simplified, flattening structures and reworking unnecessarily
+  fallible operations where possible.
+- Includes version `1` of the hugr serialization schema. Older pre-v1 serialized
+  hugrs are no longer supported. Starting with `v1`, backward compatibility for
+  loading older versions will be maintained.
 
 ### New Contributors
 
@@ -18,6 +27,8 @@ This release includes multiple breaking changes to the API, including the rename
 - HUGR spec copyediting ([#843](https://github.com/CQCL/hugr/pull/843))
 - Add builder module docs + example ([#853](https://github.com/CQCL/hugr/pull/853))
 - Add note on serialized hugr node order ([#849](https://github.com/CQCL/hugr/pull/849))
+- Specify direct children in `HugrView::children` ([#921](https://github.com/CQCL/hugr/pull/921))
+- Add logo svg to readme and spec ([#925](https://github.com/CQCL/hugr/pull/925))
 
 ### Features
 
@@ -37,6 +48,8 @@ This release includes multiple breaking changes to the API, including the rename
 - [**breaking**] Return the type of FuncDecl in `HugrView::get_function_type` ([#880](https://github.com/CQCL/hugr/pull/880))
 - [**breaking**] Merge `Value` into `Const` ([#881](https://github.com/CQCL/hugr/pull/881))
 - Replace `Tuple` with unary sums ([#891](https://github.com/CQCL/hugr/pull/891))
+- [**breaking**] No polymorphic closures ([#906](https://github.com/CQCL/hugr/pull/906))
+- [**breaking**] Flatten `LeafOp` ([#922](https://github.com/CQCL/hugr/pull/922))
 
 ### Performance
 
@@ -48,6 +61,8 @@ This release includes multiple breaking changes to the API, including the rename
 - Remove clone in `ExtensionSet::union` ([#859](https://github.com/CQCL/hugr/pull/859))
 - Extension Inference: make fewer things public, rm Meta::new ([#883](https://github.com/CQCL/hugr/pull/883))
 - [**breaking**] Return impl trait in Rewrite trait ([#889](https://github.com/CQCL/hugr/pull/889))
+- Combine ExtensionSolutions (no separate closure) ([#884](https://github.com/CQCL/hugr/pull/884))
+- [**breaking**] Merge `CustomOp` and `ExternalOp`. ([#923](https://github.com/CQCL/hugr/pull/923))
 
 ## 0.2.0 (2024-02-20)
 

hugr/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "hugr"
-version = "0.3.0-alpha.1"
+version = "0.3.0"
 edition = { workspace = true }
 rust-version = { workspace = true }