Add auto release flow

Author: kanga333

.github/workflows/release.yml

@@ -1,24 +1,36 @@
 on:
   push:
-    tags:
-      - 'v*' # Push events to matching v*, i.e. v1.0, v20.15.10
-
-name: Create Release
+    branches:
+      - main
+    paths:
+      - "package.json"
 
+name: Create Release if version is bumped
 jobs:
   build:
     name: Create Release
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
         uses: actions/checkout@v2
+      - run: git fetch --prune --unshallow --tags
+      - uses: kanga333/config-value-exporter@main
+        id: version
+        with:
+          key: version
+          file: package.json
+      - id: tag_check
+        run: |
+          git rev-parse ${{steps.version.outputs.result}} 2> /dev/null \
+            || echo '::set-output name=exist::false'
       - name: Create Release
+        if: steps.tag_check.outputs.exist == 'false'
         id: create_release
         uses: actions/create-release@v1
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:
-          tag_name: ${{ github.ref }}
-          release_name: Release ${{ github.ref }}
+          tag_name: ${{steps.version.outputs.result}}
+          release_name: Release ${{steps.version.outputs.result}}
           draft: false
           prerelease: false