update workflow

Author: FUjr

.github/workflows/main.yml

@@ -12,6 +12,15 @@ on:
       - "README.en.md"
       - ".github/workflows/**"
       - ".github/**"
+  pull_request:
+    branches:
+      - main
+    paths-ignore:
+      - "docs/**"
+      - "README.md"
+      - "README.en.md"
+      - ".github/workflows/**"
+      - ".github/**"
 
 env:
   TZ: Asia/Shanghai