Enable CD for publishing a new release

.github/workflows/python-package.yml

@@ -78,3 +78,32 @@ jobs:
         TOXENV: ${{ matrix.toxenv }}
       run: |
         tox
+
+  cd:
+    needs: ci
+    if: github.event_name == 'push' && (startsWith(github.ref, 'refs/tags') || github.ref == 'refs/heads/master')
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python 3.9
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.9
+    - name: Build a package for release
+      run: |
+        python -m pip install build --user
+        python -m build --sdist --wheel --outdir dist/ .
+    - name: Publish to TestPyPI
+      uses: pypa/gh-action-pypi-publish@v1.4.2
+      if: github.ref == 'refs/heads/master'
+      with:
+        user: __token__
+        password: ${{ secrets.TEST_PYPI_API_TOKEN }}
+        repository_url: https://test.pypi.org/legacy/
+    - name: Publish to PyPI
+      if: startsWith(github.ref, 'refs/tags')
+      uses: pypa/gh-action-pypi-publish@v1.4.2
+      with:
+        user: __token__
+        password: ${{ secrets.PYPI_API_TOKEN }}
+