add workflow to publish to PyPI on tag

.github/workflows/publish-on-pypi.yml

@@ -0,0 +1,39 @@
+name: Publish to TestPyPI and if new version PyPI
+
+on:
+  push:
+    branches: [ master ]
+jobs:
+  build-n-publish:
+    name: Build and publish to TestPyPI and PyPI
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@master
+    - name: Set up Python 3
+      uses: actions/setup-python@v1
+      with:
+        python-version: 3
+    - 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 to Test PyPI
+      uses: pypa/gh-action-pypi-publish@master
+      with:
+        password: ${{ secrets.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@master
+      with:
+        password: ${{ secrets.PYPI_API_TOKEN }}