Add the release workflow

.github/workflows/release.yml

@@ -0,0 +1,35 @@
+name: publish python distribution to pypi 
+
+on:
+  release:
+    types: [published]
+
+jobs: 
+  build-n-publish:
+    name: build and publish to pypi
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@master
+    - name: setup python 3.7
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.7
+    - name: install pypa/build
+      run: >- 
+        python -m 
+        pip install 
+        build 
+        --user
+    - name: build a binary wheel and 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 }}