Adapt to changed branch name

Author: aboks

.github/workflows/ci.yml

@@ -2,9 +2,9 @@ name: Continuous Integration
 
 on:
   push:
-    branches: [ master ]
+    branches: [ main ]
   pull_request:
-    branches: [ master ]
+    branches: [ main ]
   release:
     types: [ created ]