Update docker/setup-buildx-action digest to a946f06

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@79abd3f86f79a9d68a23c75a09a9a85889262adf
+        uses: docker/setup-buildx-action@a946f06b5ddbde456d0115dc585e8dc3c7a0c3e0
 
       # Login against a Docker registry except on PR
       # https://github.com/docker/login-action