Add publish workflow

.github/workflows/publish.yaml

@@ -0,0 +1,25 @@
+name: Publish
+
+on:
+  release:
+    types:
+      - created
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: "3.9"
+      - name: Install Flit
+        run: pip install flit
+      - name: Install Dependencies
+        run: flit install --symlink
+      - name: Publish
+        env:
+          FLIT_USERNAME: ${{ secrets.FLIT_USERNAME }}
+          FLIT_PASSWORD: ${{ secrets.FLIT_PASSWORD }}
+        run: flit publish