Update docker/setup-buildx-action digest to 8998bbe

Author: renovate[bot]

.github/workflows/ghcr-io-docker-build.yaml

@@ -36,7 +36,7 @@ jobs:
 
       # Workaround: https://github.com/docker/build-push-action/issues/461
       - name: Setup Docker buildx
-        uses: docker/setup-buildx-action@0f069ddc17b8eb78586b08a7fe335fd54649e2d3
+        uses: docker/setup-buildx-action@8998bbe94b815f234f11364561c6860c1c44bd37
 
       # Login against a Docker registry except on PR
       # https://github.com/docker/login-action