fix: use upstream docs workflow

.github/workflows/docs_rtd.yaml

@@ -35,7 +35,10 @@ jobs:
     name: Automatic doc checks
     needs: check-makefile
     if: ${{ needs.check-makefile.outputs.makefile-exists == 'true' }}
-    uses: canonical/sphinx-docs-starter-pack/.github/workflows/automatic-doc-checks.yml@dev
+    uses: canonical/documentation-workflows/.github/workflows/documentation-checks.yaml@main
+    with:
+      working-directory: "docs"
+      fetch-depth: 0
   check-removed-urls:
     name: Check removed URLs
     needs: check-makefile

docs/changelog.md

@@ -6,6 +6,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 Each revision is versioned by the date of the revision.
 
+## 2026-01-28
+- Update `docs_rtd` workflow to use `canonical/documentation-workflows/.github/workflows/documentation-checks.yaml@main`.
+
 ## 2026-01-21
 - Add `docs_spread` workflow to auto-generate testing materials and run Spread.