ci: change default branch from main to master in workflow

Author: lzwjava

.github/workflows/maven.yml

@@ -2,9 +2,9 @@ name: Compile
 
 on:
   push:
-    branches: [ "main" ]
+    branches: [ "master" ]
   pull_request:
-    branches: [ "main" ]
+    branches: [ "master" ]
   workflow_dispatch:
 
 jobs: