Include 'master' branch in CI triggers

Update .github/workflows/ci.yml to also trigger CI on the 'master' branch for both push and pull_request events. This ensures CI runs for repositories or workflows that still use 'master' alongside 'main'.

Author: C-Achard

.github/workflows/ci.yml

@@ -4,9 +4,11 @@ on:
   pull_request:
     branches:
       - main
+      - master
   push:
     branches:
       - main
+      - master
 
 jobs:
   unit: