codeql: fix branch name to run workflow

Author: andrepuschmann

.github/workflows/codeql.yml

@@ -2,10 +2,10 @@ name: "CodeQL"
 
 on:
   push:
-    branches: [ "master" ]
+    branches: [ "main" ]
   pull_request:
     # The branches below must be a subset of the branches above
-    branches: [ "master" ]
+    branches: [ "main" ]
   schedule:
     - cron: '38 10 * * 2'