add deploy job to workflow

.github/workflows/python-build.yml

@@ -15,3 +15,24 @@ jobs:
       run: python -m pip install .[dev] --upgrade pip
     - name: Test with pytest
       run: pytest
+
+  deploy:
+
+    if: startsWith(github.ref, 'refs/tags')
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Set up Python 3.8
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.8
+    - name: Build package distribution
+      run: |
+        python -m pip install build --upgrade pip
+        python -m build --sdist --wheel --outdir dist/ .
+    - name: Publish package distribution to PyPI
+      uses: pypa/gh-action-pypi-publish@main
+      with:
+        skip_existing: true
+        user: __token__
+        password: ${{ secrets.PYPI_API_TOKEN }}