Automate PyPI release on a tag

.github/workflows/pypi-release.yml

@@ -0,0 +1,37 @@
+name: Release library as a PyPI wheel and sdist on tag
+
+on:
+  release:
+    types: [created]
+
+jobs:
+  build-n-publish:
+    name: Build and publish library to PyPI
+    runs-on: ubuntu-20.04
+
+steps:
+    - uses: actions/checkout@master
+    - name: Set up Python
+      uses: actions/setup-python@v1
+      with:
+        python-version: 3.8
+    - name: Install pypa/build
+      run: >-
+        python -m
+        pip install
+        build
+        --user
+    - name: Build a binary wheel and a source tarball
+      run: >-
+        python -m
+        build
+        --sdist
+        --wheel
+        --outdir dist/
+        .
+    - name: Publish distribution  to PyPI
+      if: startsWith(github.ref, 'refs/tags')
+      uses: pypa/gh-action-pypi-publish@master
+      with:
+        password: ${{ secrets.PYPI_API_TOKEN }}
+