Update CI.yml (#53)

I need to have workflow dispatch enabled to debug CI GitHub Actions, specially Documentation workflow.

Author: storopoli

.github/workflows/CI.yml

@@ -5,6 +5,7 @@ on:
       - main
     tags: '*'
   pull_request:
+  workflow_dispatch:
 concurrency:
   # Skip intermediate builds: always.
   # Cancel intermediate builds: only if it is a pull request build.