add semver tag and rebuild on dockerfile change

.github/workflows/docker-publish.yml

@@ -64,10 +64,13 @@ jobs:
         uses: docker/metadata-action@96383f45573cb7f253c731d3b3ab81c87ef81934 # v5.0.0
         with:
           images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags:
+            type=semver,pattern={{version}},value=v1.0.0
 
       # Build and push Docker image with Buildx (don't push on PR)
       # https://github.com/docker/build-push-action
       - name: Build and push Docker image
+        if: ${{ github.event_name != 'pull_request' && contains(github.event.head_commit, 'Dockerfile')}}
         id: build-and-push
         uses: docker/build-push-action@0565240e2d4ab88bba5387d719585280857ece09 # v5.0.0
         with:
@@ -84,7 +87,7 @@ jobs:
       # transparency data even for private images, pass --force to cosign below.
       # https://github.com/sigstore/cosign
       - name: Sign the published Docker image
-        if: ${{ github.event_name != 'pull_request' }}
+        if: ${{ github.event_name != 'pull_request' && contains(github.event.head_commit, 'Dockerfile')}}
         env:
           # https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#using-an-intermediate-environment-variable
           TAGS: ${{ steps.meta.outputs.tags }}