Update mdbook.yml

Author: ratulb

.github/workflows/mdbook.yml

@@ -8,7 +8,9 @@ on:
  # Runs on pushes targeting the default branch
  push:
  branches: ["main"]
-
+ pull_request:
+ branches: ["main"]
+ 
  # Allows you to run this workflow manually from the Actions tab
  workflow_dispatch: