Add GitHub Actions workflow for making a release (#97)

This PR adds a GitHub Actions workflow for building wheel and sdist and
uploading to PyPI on release.

Also adds a note to the changelog indicating that it's now historical.

.github/workflows/release.yml

@@ -0,0 +1,24 @@
+name: Release
+
+on:
+  workflow_dispatch:
+  release:
+    types: [published]
+
+jobs:
+  build-and-upload:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-python@v4
+      with:
+        python-version: '3.12'
+    - run: python -m pip install build twine
+    - run: python -m build
+    - run: |
+        python -m twine check --strict dist/*
+        python -m twine upload dist/*
+      env:
+        TWINE_USERNAME: ${{ secrets.PYPI_USERNAME }}
+        TWINE_PASSWORD: ${{ secrets.PYPI_PASSWORD }}

CHANGES

@@ -1,3 +1,6 @@
+This file contains historical changes up to release 0.2.1.
+For more recent changes see the release notes on GitHub.
+
 Refcycle changelog
 ==================