Update CI.yml

Author: heltonmc

.github/workflows/CI.yml

@@ -1,10 +1,12 @@
 name: CI
 on:
+  pull_request:
+    branches:
+      - main
   push:
     branches:
       - main
     tags: '*'
-  pull_request:
 concurrency:
   # Skip intermediate builds: always.
   # Cancel intermediate builds: only if it is a pull request build.