Update docker/setup-buildx-action action to v4 (#851)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Michal Kielbowicz <michal.kielbowicz@sourcegraph.com>

Author: renovate[bot]

.github/workflows/release-docker.yaml

@@ -24,7 +24,7 @@ jobs:
         with:
           fetch-depth: 0
 
-      - uses: docker/setup-buildx-action@v3
+      - uses: docker/setup-buildx-action@v4
 
       - name: Login to GitHub Container Registry
         uses: docker/login-action@v4