fix: skip installing Buildx when possible

.github/workflows/docker.yaml

@@ -79,6 +79,7 @@ jobs:
           ref: ${{ steps.check.outputs.ref }}
       -
         name: Set up Docker Buildx
+        if: ${{ !fromJson(steps.check.outputs.skip) }}
         uses: docker/setup-buildx-action@v3
         with:
           version: latest