ci: add documentation checks

.github/workflows/automatic-doc-checks.yml

@@ -0,0 +1,16 @@
+name: Main Documentation Checks
+
+on:
+  - push
+  - pull_request
+  - workflow_dispatch
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true  
+
+jobs:
+  documentation-checks:
+    uses: canonical/documentation-workflows/.github/workflows/documentation-checks.yaml@main
+    with:
+      working-directory: doc/sphinx