build(deps): bump docker/bake-action from 6 to 7

Bumps [docker/bake-action](https://github.com/docker/bake-action) from 6 to 7.
- [Release notes](https://github.com/docker/bake-action/releases)
- [Commits](https://github.com/docker/bake-action/compare/v6...v7)

---
updated-dependencies:
- dependency-name: docker/bake-action
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/docs-upstream.yml

@@ -46,7 +46,7 @@ jobs:
           buildkitd-flags: --debug
       -
         name: Build reference YAML docs
-        uses: docker/bake-action@v6
+        uses: docker/bake-action@v7
         with:
           targets: update-docs
           provenance: false