Use macOS 13 for CI

since macOS 12 runners were removed from MS GitHub Actions

Author: dmbaturin

.github/workflows/main.yml

@@ -15,7 +15,7 @@ jobs:
   # This workflow contains a single job called "build"
   build:
     # The type of runner that the job will run on
-    runs-on: macos-12
+    runs-on: macos-13
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps: