feat: fix CI: restrict release-and-push job to master branch only (#102)

Author: Copilot

.github/workflows/build.yml

@@ -60,7 +60,7 @@ jobs:
   release-and-push:
     name: Release And Push
     runs-on: ubuntu-latest
-    if: github.repository == 'casbin/caswaf' && github.event_name == 'push'
+    if: github.repository == 'casbin/caswaf' && github.event_name == 'push' && github.ref == 'refs/heads/master'
     needs: [ frontend, backend]
     steps:
       - name: Checkout
@@ -104,14 +104,14 @@ jobs:
 
       - name: Log in to Docker Hub
         uses: docker/login-action@v1
-        if: github.repository == 'casbin/caswaf' && github.event_name == 'push' && steps.should_push.outputs.push=='true'
+        if: github.repository == 'casbin/caswaf' && github.event_name == 'push' && github.ref == 'refs/heads/master' && steps.should_push.outputs.push=='true'
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_PASSWORD }}
 
       - name: Push to Docker Hub
         uses: docker/build-push-action@v3
-        if: github.repository == 'casbin/caswaf' && github.event_name == 'push' && steps.should_push.outputs.push=='true'
+        if: github.repository == 'casbin/caswaf' && github.event_name == 'push' && github.ref == 'refs/heads/master' && steps.should_push.outputs.push=='true'
         with:
           context: .
           target: STANDARD