feat(ci): simplify image tag

.github/workflows/build.yaml

@@ -13,26 +13,10 @@ permissions:
 jobs:
   build:
     runs-on: ubuntu-latest
-    outputs:
-      tag: ${{ steps.vars.outputs.image-tag }}
-      application: ${{ steps.vars.outputs.application }}
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Set variables
-        id: vars
-        env:
-          EVENT_NAME: ${{ github.event_name }}
-          REF_TYPE: ${{ github.ref_type }}
-          REF_NAME: ${{ github.ref_name }}
-          GIT_SHA: ${{ github.sha }}
-        run: |
-          date="$(date -u +%Y%m%d)"
-          short_rev="$(git rev-parse --short "$GIT_SHA")"
-          echo "image-tag=${REF_NAME}" >> $GITHUB_OUTPUT
-          echo "application=bacchus-snu/snucse" >> $GITHUB_OUTPUT
-
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v2
       - name: Configure registry credentials
@@ -41,11 +25,18 @@ jobs:
           registry: ghcr.io
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Set variables
+        uses: docker/metadata-aciton#
+        id: meta
+        with:
+          images: ghcr.io/bacchus-snu/${{ vars.IMAGE_NAME }}
       - name: Build and push
         uses: docker/build-push-action@v4
         with:
           context: .
           push: ${{ github.event_name != 'pull_request' }}
-          tags: ghcr.io/bacchus-snu/${{ vars.IMAGE_NAME }}:${{ steps.vars.outputs.image-tag }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
           cache-from: type=gha
           cache-to: type=gha,mode=max