Add CI workflow to check docs (backport #164) (#369)

Co-authored-by: Christoph Fröhlich <[email protected]>

.github/workflows/ci-check-docs.yml

@@ -0,0 +1,12 @@
+name: Check Docs
+
+on:
+  workflow_dispatch:
+  pull_request:
+
+jobs:
+  check-docs:
+    name: Check Docs
+    uses: ros-controls/control.ros.org/.github/workflows/reusable-sphinx-check-single-version.yml@humble
+    with:
+      GZ_ROS2_CONTROL_PR: ${{ github.ref }}