Update build_main.yml

.github/workflows/build_main.yml

@@ -1,7 +1,7 @@
 name: Build Main
-on push:
-  branches:
-    - main
+on:
+  push:
+    branches: [ main ]
 jobs:
   build:
     runs-on: ubuntu-latest
@@ -20,4 +20,4 @@ jobs:
       - uses: actions/upload-artifact@v2
         with:
           name: Extension-XPI
-          path: web-ext-artifacts/firefox_translations-*.zip
+          path: web-ext-artifacts/firefox_translations-*.zip