fix(ci): publish container images to GHCR only

.github/workflows/backend-latest.yml

@@ -1,4 +1,4 @@
-name: Upload latest backend image to GHCR and Docker Hub
+name: Upload latest backend image to GHCR
 
 permissions:
   contents: read
@@ -30,12 +30,6 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Login to Docker Hub
-        uses: docker/login-action@v3
-        with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
-
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
 
@@ -50,7 +44,6 @@ jobs:
           push: true
           tags: |
             ghcr.io/${{ github.repository_owner }}/${{ env.IMAGE_NAME }}:latest
-            ${{ secrets.DOCKERHUB_USERNAME }}/${{ env.IMAGE_NAME }}:latest
           cache-from: |
             type=registry,ref=ghcr.io/${{ github.repository_owner }}/${{ env.IMAGE_NAME }}:buildcache
             type=local,src=/tmp/.buildx-cache