build zips on tag push

.github/workflows/build-packages.yml

@@ -0,0 +1,67 @@
+name: Release starter and migration packages on tag push
+
+on:
+  push:
+    tags: [ '*' ]
+
+jobs:
+  zip-and-release-packages:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Set release version
+        run: echo "RELEASE_VERSION=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV
+
+      - name: Prepare release folder
+        run: |
+          mkdir packages
+
+      - name: Zip starter
+        uses: montudor/action-zip@v1
+        with:
+          args: >
+            zip -r packages/starter.zip . \
+                \
+                -x "*.git/*" \
+                -x ".github/*" \
+                -x "spotless/*" \
+                -x "docs/*" \
+                \
+                -x "CODEOWNERS" \
+                -x "LICENSE" \
+                -x "README.md" \
+                \
+                -x "packages/" \
+                -x "packages/starter.zip" \
+                -x "packages/migration.zip"
+
+      - name: Zip migration
+        uses: montudor/action-zip@v1
+        with:
+          args: >
+            zip -r packages/migration.zip . \
+                \
+                -x "*.git/*" \
+                -x ".github/*" \
+                -x "spotless/*" \
+                -x "docs/*" \
+                -x "src/*" \
+                \
+                -x "CODEOWNERS" \
+                -x "LICENSE" \
+                -x "README.md" \
+                \
+                -x "packages/" \
+                -x "packages/starter.zip" \
+                -x "packages/migration.zip"
+
+      - name: Release tag
+        uses: marvinpinto/action-automatic-releases@latest
+        with:
+          repo_token: "${{ secrets.GITHUB_TOKEN }}"
+          automatic_release_tag: "${{ env.RELEASE_VERSION }}-packages"
+          prerelease: false
+          title: "${{ env.RELEASE_VERSION }} starter and migration packages"
+          files: packages/*