fix: update branch name in CI workflow

Changed the branch name from 'main' to 'master' in the CI configuration file to align with the repository's default branch naming convention.

Signed-off-by: Jens Oliver Meiert <[email protected]>

.github/workflows/tests.yml

@@ -3,7 +3,7 @@ name: Tests
 on:
   pull_request:
     branches:
-      - main
+      - master
 
 jobs:
   test: