Switch to macOS 14 in CI

Author: flashcode

.github/workflows/ci.yml

@@ -83,7 +83,7 @@ jobs:
     strategy:
       matrix:
         os:
-          - macos-12
+          - macos-14
         config:
           - { name: "gcc", cc: "gcc", cxx: "g++", cmake_options: "" }
           - { name: "clang", cc: "clang", cxx: "clang++", cmake_options: "" }