Add a GitHub Actions-based release workflow

This is based on
https://packaging.python.org/en/latest/guides/publishing-package-distribution-releases-using-github-actions-ci-cd-workflows/#defining-a-workflow-job-environment
. It's the sample config from there, with versions updated and
our project name substituted in the appropriate places. I dropped
the publish-to-testpypi bit because of
pypa/packaging.python.org#804 , and left
the Github release part left out for now. We can add that later if
we like, but we never published releases to Github before, so it
doesn't seem required yet. I also tweaked the conditionals a bit
to avoid running the build job on forks and publish only tags
that start with 'v', as that's our convention for versions.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

.github/workflows/release.yml

@@ -0,0 +1,47 @@
+name: Build and publish Python distribution to PyPI and TestPyPI
+
+on: push
+
+jobs:
+  build:
+    name: Build distribution
+    if: startsWith(github.ref, 'refs/tags/v') # only publish to PyPI on version tag pushes
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python
+      uses: actions/setup-python@v5.1.0
+      with:
+        python-version: "3.x"
+
+    - name: Install pypa/build
+      run: python3 -m pip install build --user
+    - name: Build a binary wheel and a source tarball
+      run: python3 -m build
+    - name: Store the distribution packages
+      uses: actions/upload-artifact@v4
+      with:
+        name: python-package-distributions
+        path: dist/
+
+  publish-to-pypi:
+    name: Publish Python distribution to PyPI
+    if: startsWith(github.ref, 'refs/tags/v') # only publish to PyPI on version tag pushes
+    needs:
+    - build
+    runs-on: ubuntu-latest
+    environment:
+      name: pypi
+      url: https://pypi.org/p/mwclient
+    permissions:
+      id-token: write  # IMPORTANT: mandatory for trusted publishing
+
+    steps:
+    - name: Download all the dists
+      uses: actions/download-artifact@v4
+      with:
+        name: python-package-distributions
+        path: dist/
+    - name: Publish distribution to PyPI
+      uses: pypa/gh-action-pypi-publish@release/v1

docs/source/development/index.rst

@@ -109,3 +109,18 @@ When it is ready, push your branch to your remote:
 
 Then you can open a pull request on GitHub. You should see a URL to do this
 when you push your branch.
+
+Making a release
+----------------
+
+These instructions are for maintainers of the project.
+To cut a release, ensure ``CHANGELOG.md`` is updated, then use
+`bump-my-version <https://callowayproject.github.io/bump-my-version/>`_:
+
+.. code:: bash
+
+    $ pip install bump-my-version
+    $ bump-my-version bump major|minor|patch
+
+Then check the commit looks correct and is tagged vX.Y.Z, and push. The
+``.github/workflows/release.yml`` action will publish to PyPI.

setup.py

@@ -10,7 +10,9 @@
 pytest_runner = ['pytest-runner'] if needs_pytest else []
 
 setup(name='mwclient',
-      version='0.10.1',  # Use bumpversion to update
+      # See https://mwclient.readthedocs.io/en/latest/development/#making-a-release
+      # for how to update this field and release a new version.
+      version='0.10.1',
       description='MediaWiki API client',
       long_description=README,
       long_description_content_type='text/markdown',