ci: add docker metadata

Author: lschloetterer

.github/workflows/build-image.yml

@@ -24,10 +24,15 @@ jobs:
       uses: actions/checkout@v4
     - name: Retrieve image version
       run: echo "IMAGE_VERSION=$(head -1 Dockerfile | grep -oP '(?<=caddy:).*?(?=-builder)')" >> $GITHUB_ENV
-    - name: Parse version ranges
-      run: |
-        echo "IMAGE_VERSION_MAJOR=$(echo $IMAGE_VERSION | cut -d '.' -f 1)" >> $GITHUB_ENV
-        echo "IMAGE_VERSION_MAJOR_MINOR=$(echo $IMAGE_VERSION | cut -d '.' -f 1,2)" >> $GITHUB_ENV
+    - name: Generate image metadata
+      id: meta
+      uses: docker/metadata-action@v5
+      with:
+        images: ${{ env.IMAGE_NAME }}
+        tags: |
+          type=semver,pattern={{version}},value=${{ env.IMAGE_VERSION }}
+          type=semver,pattern={{major}}.{{minor}},value=${{ env.IMAGE_VERSION }}
+          type=semver,pattern={{major}},value=${{ env.IMAGE_VERSION }}
     - name: Set up QEMU
       uses: docker/setup-qemu-action@v3
     - name: Set up Docker Buildx
@@ -43,8 +48,5 @@ jobs:
       with:
         platforms: ${{ env.PLATFORMS }}
         push: true
-        tags: |
-          ${{ env.IMAGE_NAME }}:${{ env.IMAGE_VERSION }}
-          ${{ env.IMAGE_NAME }}:${{ env.IMAGE_VERSION_MAJOR }}
-          ${{ env.IMAGE_NAME }}:${{ env.IMAGE_VERSION_MAJOR_MINOR }}
-          ${{ env.IMAGE_NAME }}:latest
+        tags: ${{ steps.meta.outputs.tags }}
+        labels: ${{ steps.meta.outputs.labels }}