Add release notes for 0.1.2.

RELEASES.md

@@ -1,3 +1,24 @@
+# Version 0.1.2
+
+The original plan to release 1.0.0 was changed so that version 0.1.1 is released and a related [RFC to fix the error trait](https://github.com/rust-lang/rfcs/pull/2504) is submitted. See README for details.
+
+- Fix `failure_derive` to work with Rust 2018.
+- Add `#[fail(cause)]` that works similarly with `#[cause]`. The new form is preferred.
+- Fix `"backtrace"` feature to work without `"std"` feature.
+- Add `Compat::get_ref`.
+- Add `Fallible`.
+- Deprecate `Fail::causes` and `<dyn Fail>::causes` in favor of newly added `<dyn Fail>::iter_causes`.
+- Deprecate `Fail::root_cause` and `<dyn Fail>::root_cause` in favor of newly added `<dyn Fail>::find_root_cause`.
+- Add `<dyn Fail>::iter_chain`.
+- Implement `Box<Fail>: Fail`.
+- Add `Error::from_boxed_compat`.
+- Deprecate `Error::cause` in favor of newly added `Error::as_fail`.
+- Deprecate `Error::causes` in favor of newly added `Error::iter_chain`.
+- Deprecate `Error::root_cause` in favor of newly added `Error::find_root_cause`.
+- Add `Error::iter_causes`.
+- Implement `Error: AsRef<Fail>`.
+- Fix `Debug` implementation of `SyncFailure`.
+
 # Version 0.1.1
 
 - Add a `Causes` iterator, which iterates over the causes of a failure. Can be