.github: rename default branch from flatcar-master to main

dongsupark · dongsupark · commit 575d51088c8a · 2025-05-27T15:29:54.000+02:00
Rename the default branch from flatcar-master to main, following the
general Flatcar repo settings guideline.

Note: we should not touch download URLs of seismograph yet, which should
be updated afterwards.
diff --git a/.github/workflows/c-cpp.yml b/.github/workflows/c-cpp.yml
@@ -2,9 +2,9 @@ name: C/C++ CI
 
 on:
   push:
-    branches: [ flatcar-master ]
+    branches: [ main ]
   pull_request:
-    branches: [ flatcar-master ]
+    branches: [ main ]
 
 jobs:
   build:
