A few more updates for index publication (#88)

* Recommend the --seed option in virtual env instructions

While `uv venv` does create a virtual environment in the standard location
(a .venv folder in the currenet directory), it does not install "seed"
packages like pep, setuptools, and wheel into it. For people used to standard
pip incantations (e.g., `pip list`), this behavior is confusing because they
now have to use `uv pip list`, even after they manually activated the uv-created
environment.

I.e., this series of commands will not produce a list of environemnt packages:
- `uv venv`
- manually activate the venv the old-fashioned way: source .venv/bin/activate
- pip list

However, passing the --seed option allows the above commands to work as
expected by people who retain muscle memory for the old ways.

* Ensure that the checkout step includes history for tags as well as branches

Cladetime is using setuptools-scm to dynamically determine the package version.
This commit address an issue with CI builds where the version was not
incorporating the latest tags.

.github/workflows/publish-pypi-test.yaml

@@ -17,6 +17,7 @@ jobs:
       - name: Checkout 🛎️
         uses: actions/checkout@v4
         with:
+          fetch-depth: 0
           persist-credentials: false
 
       - name: Set up Python 🐍

CONTRIBUTING.md

@@ -46,7 +46,7 @@ will install the version of Python specified in
 [.python-version](.python-version).
 
     ```bash
-    uv venv
+    uv venv --seed
     ```
 
 5. Install the project's dependencies, including an editable copy of the