Docs Sync CI - Add on-demand trigger (#5695)

* Add on-demand trigger

* Add doc request template

.github/ISSUE_TEMPLATE/doc_update.md

@@ -0,0 +1,16 @@
+---
+name: Documentation Request
+about: Let us know what our docs can improve
+title: ''
+labels: 'documentation'
+assignees: ''
+---
+
+**Is some content missing, wrong or not clear?**
+A clear and concise description of what the problem is and the source URL. Ex. Page [...] is not clear.
+
+**Describe the solution you'd like**
+Let us know what could help us improve the docs.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.

.github/workflows/sync-docs.yml

@@ -16,6 +16,7 @@ on:
     branches: [main]
     paths:
       - openmetadata-docs/**
+  workflow_dispatch:
 
 jobs:
   sync-docs: