chore(docker): use docker meta for tagging for GHCR

.github/workflows/docker.yml

@@ -4,15 +4,31 @@ on:
   push:
     branches:
       - main
+  pull_request:
+    branches:
+      - main
 
 jobs:
-  docker-hub:
-    name: Docker Hub
+  docker:
+    name: Docker Build and Push
     runs-on: ubuntu-20.04
     steps:
       - name: Checkout
         uses: actions/checkout@v2
 
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v3
+        with:
+          images: |
+            ${{ secrets.DOCKER_HUB_USERNAME }}/git-cliff:latest
+            ghcr.io/${{ github.repository_owner }}/git-cliff:latest
+          tags: |
+            type=schedule
+            type=ref,event=branch
+            type=ref,event=pr
+            type=sha
+
       - name: Set up Docker Buildx
         id: buildx
         uses: docker/setup-buildx-action@v1
@@ -26,20 +42,30 @@ jobs:
             ${{ runner.os }}-buildx-
 
       - name: Login to Docker Hub
+        if: github.event_name != 'pull_request'
         uses: docker/login-action@v1
         with:
           username: ${{ secrets.DOCKER_HUB_USERNAME }}
           password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}
 
+      - name: Login to GHCR
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
       - name: Build and push
         id: docker_build
         uses: docker/build-push-action@v2
         with:
           context: ./
           file: ./Dockerfile
           builder: ${{ steps.buildx.outputs.name }}
-          push: true
-          tags: ${{ secrets.DOCKER_HUB_USERNAME }}/git-cliff:latest
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
           cache-from: type=local,src=/tmp/.buildx-cache
           cache-to: type=local,dest=/tmp/.buildx-cache