Update .gitea/workflows/main.yaml

.gitea/workflows/main.yaml

@@ -1,6 +1,12 @@
 name: Build Mau & Deploy Mau
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - 'mauster'
+  pull_request:
+    types:
+      - opened
 
 concurrency:
   group: mau