ci: use edge releases of buildx

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

.github/workflows/docs-upstream.yml

@@ -29,6 +29,10 @@ on:
       - '.github/workflows/docs-upstream.yml'
       - 'docs/**'
 
+env:
+  SETUP_BUILDX_VERSION: "edge"
+  SETUP_BUILDKIT_IMAGE: "moby/buildkit:latest"
+
 jobs:
   docs-yaml:
     runs-on: ubuntu-24.04
@@ -40,7 +44,9 @@ jobs:
         name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
         with:
-          version: latest
+          version: ${{ env.SETUP_BUILDX_VERSION }}
+          driver-opts: image=${{ env.SETUP_BUILDKIT_IMAGE }}
+          buildkitd-flags: --debug
       -
         name: Build reference YAML docs
         uses: docker/bake-action@v5