Update docker/setup-buildx-action digest to 7703e82

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@7703e82fbced3d0c9eec08dff4429c023a5fd9a9
 
       # Login against a Docker registry except on PR
       # https://github.com/docker/login-action