Update docker/setup-buildx-action digest to 39a1a82 (#68)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

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@bea6a01aa40b4d58b0382d47e1c4a70137af67b1
+        uses: docker/setup-buildx-action@39a1a82492fd1ad19af19d61b5f748e4cb6cd1af
 
       # Login against a Docker registry except on PR
       # https://github.com/docker/login-action