Refactor GitHub Actions workflow for Docker builds

.github/workflows/build.yml

@@ -272,7 +272,17 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        docker-rev: ["Dockerfile", "Dockerfile.ultra-lite", "Dockerfile.fat"]
+        docker-rev: 
+          # - name: regular
+          #   file: ./Dockerfile
+          #   additional_tags: ""
+          # - name: ultra-lite
+          #   file: ./Dockerfile.ultra-lite
+          #   additional_tags: ""
+          - name: fat
+            file: ./Dockerfile.fat
+            additional_tags: |
+              type=raw,value=alpha,enable=${{ github.ref == 'refs/heads/main' }}
     steps:
       - name: Harden Runner
         uses: step-security/harden-runner@95d9a5deda9de15063e7595e9719c11c38c90ae2 # v2.13.2
@@ -306,19 +316,36 @@ jobs:
       - name: Set up QEMU
         uses: docker/setup-qemu-action@c7c53464625b32c7a7e944ae62b3e17d2b600130 # v3.7.0
 
+      - name: Convert repository owner to lowercase
+        id: repoowner
+        run: echo "lowercase=$(echo ${{ github.repository_owner }} | awk '{print tolower($0)}')" >> $GITHUB_OUTPUT
+
+      - name: Generate tags (${{ matrix.docker-rev.name }})
+        id: meta
+        uses: docker/metadata-action@318604b99e75e41977312d83839a89be02ca4893 # v5.9.0
+        with:
+          images: |
+            ${{ secrets.DOCKER_HUB_USERNAME }}/s-pdf
+            ghcr.io/${{ steps.repoowner.outputs.lowercase }}/s-pdf
+            ghcr.io/${{ steps.repoowner.outputs.lowercase }}/stirling-pdf
+            ${{ secrets.DOCKER_HUB_ORG_USERNAME }}/stirling-pdf
+          tags: |
+            ${{ matrix.docker-rev.additional_tags }}
+
       - name: Set up Docker Buildx
         id: buildx
         uses: docker/setup-buildx-action@e468171a9de216ec08956ac3ada2f0791b6bd435 # v3.11.1
 
-      - name: Build ${{ matrix.docker-rev }}
+      - name: Build ${{ matrix.docker-rev.name }}
         uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
         with:
           builder: ${{ steps.buildx.outputs.name }}
           context: .
-          file: ./${{ matrix.docker-rev }}
+          file: ${{ matrix.docker-rev.file }}
           push: false
           cache-from: type=gha
           cache-to: type=gha,mode=max
+          tags: ${{ steps.meta.outputs.tags }}
           build-args: VERSION_TAG=${{ steps.versionNumber.outputs.versionNumber }}
           platforms: linux/amd64,linux/arm64/v8
           provenance: true