add semver tag and rebuild on dockerfile change

.github/workflows/docker-publish.yml

@@ -20,7 +20,7 @@ env:
 
 jobs:
   build:
-
+    if: ${{ github.event_name != 'pull_request' && contains(github.event.head_commit.modified, 'Dockerfile')}}
     runs-on: ubuntu-latest
     permissions:
       contents: read
@@ -36,7 +36,6 @@ jobs:
       # Install the cosign tool except on PR
       # https://github.com/sigstore/cosign-installer
       - name: Install cosign
-        if: github.event_name != 'pull_request'
         uses: sigstore/cosign-installer@6e04d228eb30da1757ee4e1dd75a0ec73a653e06 #v3.1.1
         with:
           cosign-release: 'v2.1.1'
@@ -50,7 +49,7 @@ jobs:
       # Login against a Docker registry except on PR
       # https://github.com/docker/login-action
       - name: Log into registry ${{ env.REGISTRY }}
-        if: github.event_name != 'pull_request'
+
         uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d # v3.0.0
         with:
           registry: ${{ env.REGISTRY }}
@@ -64,6 +63,8 @@ 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
@@ -84,7 +85,6 @@ 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' }}
         env:
           # https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#using-an-intermediate-environment-variable
           TAGS: ${{ steps.meta.outputs.tags }}