CI: build only on macos-14

.github/workflows/build-macos.yml

@@ -12,13 +12,10 @@ env:
 
 jobs:
   build:
-    strategy:
-      matrix:
-        os: [ macos-11, macos-12, macos-13, macos-14 ]
     # The CMake configure and build commands are platform agnostic and should work equally well on Windows or Mac.
     # You can convert this to a matrix build if you need cross-platform coverage.
     # See: https://docs.github.com/en/free-pro-team@latest/actions/learn-github-actions/managing-complex-workflows#using-a-build-matrix
-    runs-on: ${{ matrix.os }} 
+    runs-on: macos-14 
     if: github.ref_name == 'main'
     steps:
     - uses: actions/checkout@v4