add Docker Hub push

Author: redenfire

.github/workflows/build.yml

@@ -17,9 +17,16 @@ jobs:
           registry: ghcr.io
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
+      - uses: docker/login-action@v3
+        with:
+          registry: docker.io
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
       - uses: docker/build-push-action@v6
         with:
           context: .
           platforms: linux/amd64,linux/arm64,linux/arm/v7
-          push: ${{ github.event_name != 'pull_request' }}
-          tags: ghcr.io/${{ github.repository }}:latest
+          push: true
+          tags: |
+            ghcr.io/${{ github.repository }}:latest
+            docker.io/${{ secrets.DOCKERHUB_USERNAME }}/docker-image-watcher:latest