used github updated at as tag

.github/workflows/docker-image.yml

@@ -21,25 +21,24 @@ jobs:
     name: Build and Push
     runs-on: ubuntu-latest
     steps:
-      - name: Set current date as env variable
-        run: echo "NOW=$(date +'%Y-%m-%dT%H:%M:%S')" >> $GITHUB_ENV
-      - name: Echo current date
-        run: echo $NOW
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
+
       - name: Login to Harbor
         uses: docker/login-action@v2
         with:
           registry: https://${{ secrets.HARBOR_REGISTRY_URL }}
           username: ${{ secrets.HARBOR_REGISTRY_USERNAME }}
           password: ${{ secrets.HARBOR_REGISTRY_PASSWORD }}
+
       - name: Build and push
         uses: docker/build-push-action@v5
         with:
           push: true
-          tags: ${{ secrets.HARBOR_REGISTRY_URL }}/baeda/timeseries-inspector:$NOW
+          tags: ${{ secrets.HARBOR_REGISTRY_URL }}/baeda/timeseries-inspector:${{ github.event.repository.updated_at}}
 
 #on:
 #  push: