Enable CI for PRs too

Author: cowtowncoder

.github/workflows/main.yml

@@ -8,6 +8,12 @@ on:
     paths-ignore:
     - "README.md"
     - "release-notes/*"
+  pull_request:
+    branches:
+    - master
+    - "3.0"
+    - "2.17"
+      
 permissions:
   contents: read