Add publish workflow

.github/workflows/publish.yml

@@ -0,0 +1,26 @@
+name: Publish
+
+on:
+  push:
+    tags:
+      - v*
+
+jobs:
+  build-n-publish:
+    name: Build and publish
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@master
+    - name: Set up Python 3.7
+      uses: actions/setup-python@v1
+      with:
+        python-version: 3.7
+    - name: Install dependencies
+      run: |
+        python -m pip install poetry
+    - name: Build a binary wheel and a source tarball
+      run: |
+        poetry build
+    - name: Publish distribution to PyPI
+      run: |
+        poetry publish -u __token__ -p ${{ secrets.pypi_password }}