ci: call docs update workflow from release (#933)

- replace the docs update tag-push trigger with manual and reusable
workflow entrypoints
- call the docs update reusable workflow after publishing a release
- keep manual docs updates available by selecting the latest semver tag

Refs: pi-session 019f2352-565c-7f60-b96b-f2546fb1690f

.github/workflows/release.yml

@@ -111,3 +111,14 @@ jobs:
 
           echo "Publishing draft release $TAG"
           gh release edit "$TAG" --draft=false
+
+  update-docs:
+    name: Update docs
+    needs:
+      - release
+    uses: ./.github/workflows/update-docs.yml
+    permissions:
+      contents: write
+      pull-requests: write
+    with:
+      tag: v${{ inputs.version }}