ci: refactor CI pipeline to remove Docker Hub dependencies

- Remove Docker Hub login step
- Remove Docker Hub image reference

Signed-off-by: appleboy <appleboy.tw@gmail.com>

.github/workflows/docker.yml

@@ -34,12 +34,6 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
-      - name: Login to Docker Hub
-        uses: docker/login-action@v3
-        with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
-
       - name: Login to GitHub Container Registry
         uses: docker/login-action@v3
         with:
@@ -52,7 +46,6 @@ jobs:
         uses: docker/metadata-action@v5
         with:
           images: |
-            ${{ github.repository }}
             ghcr.io/${{ github.repository }}
           tags: |
             type=raw,value=latest,enable={{is_default_branch}}