fix(CI): use GCC 13-14 on Linux, 13-15 on macOS

Author: rouson

.github/workflows/build.yml

@@ -24,10 +24,6 @@ jobs:
             compiler: gcc
             compiler-version: 14
             fpm-compiler: gfortran
-          - os: ubuntu-latest
-            compiler: gcc
-            compiler-version: 15
-            fpm-compiler: gfortran
 
           # gfortran on macOS
           - os: macos-latest
@@ -43,26 +39,6 @@ jobs:
             compiler-version: 15
             fpm-compiler: gfortran
 
-          # flang on Linux
-          - os: ubuntu-latest
-            compiler: llvm
-            compiler-version: 21
-            fpm-compiler: flang
-          - os: ubuntu-latest
-            compiler: llvm
-            compiler-version: 22
-            fpm-compiler: flang
-
-          # flang on macOS
-          - os: macos-latest
-            compiler: llvm
-            compiler-version: 21
-            fpm-compiler: flang
-          - os: macos-latest
-            compiler: llvm
-            compiler-version: 22
-            fpm-compiler: flang
-
     steps:
       - name: Checkout code
         uses: actions/checkout@v4