Update docker/setup-buildx-action digest to 6524bf6

Author: renovate[bot]

.github/workflows/docker-publish.yml

@@ -48,7 +48,7 @@ jobs:
 
       # Workaround: https://github.com/docker/build-push-action/issues/461
       - name: Setup Docker buildx
-        uses: docker/setup-buildx-action@20111c644724909db5e5afbf25d7de40ddf74f0b
+        uses: docker/setup-buildx-action@6524bf65af31da8d45b59e8c27de4bd072b392f5
 
       # Login against a Docker registry except on PR
       # https://github.com/docker/login-action