[CI] Upgrade gfortran on Mac

Author: amontoison

.github/workflows/ci.yml

@@ -44,7 +44,7 @@ jobs:
         uses: fortran-lang/setup-fortran@main
         with:
           compiler: 'gcc'
-          version: '12'
+          version: '14'
         if: matrix.os == 'macos-latest' || matrix.os == 'macos-13'
       - uses: julia-actions/setup-julia@v2
         with: