Replace master with main branch (#11629)

Motivation:

We should not use master as branch name, better to switch to main

Modifications:

Replace master branch name with main

Result:

Use main as replacement for master

.github/workflows/ci-build.yml

@@ -17,7 +17,7 @@ name: Build project
 
 on:
   push:
-    branches: [ "4.1"]
+    branches: [ "main"]
 
   schedule:
     - cron: '30 1 * * 1'  # At 01:30 on Monday, every Monday.

.github/workflows/codeql-analysis.yml

@@ -22,10 +22,10 @@ name: "CodeQL"
 
 on:
   push:
-    branches: ["4.1", master]
+    branches: ["4.1", main]
   pull_request:
     # The branches below must be a subset of the branches above
-    branches: ["4.1", master]
+    branches: ["4.1", main]
   schedule:
     - cron: '0 13 * * 3'