chore: macos runs-on

Author: Masaiki

.github/workflows/c-cpp.yml

@@ -16,7 +16,7 @@ jobs:
           cmake --build build --clean-first
 
   build-macos:
-    runs-on: macos-10.15
+    runs-on: macos-12
     steps:
       - uses: actions/checkout@v2
       - name: install deps