Add a release script (#23)

.github/workflows/release.yml

@@ -0,0 +1,33 @@
+name: Publish to PyPi
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - 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: pypi-publish
+        if: startsWith(github.ref, 'refs/tags')
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          password: ${{ secrets.PYPI_TOKEN }}