[ci] update gcc version when testing emulated arch

Author: serge-sans-paille

.github/workflows/emulated.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       matrix:
         sys:
-          - { compiler: 'gcc',   version: '14'}
+          - { compiler: 'gcc',   version: '15'}
           - { compiler: 'clang', version: '18'}
     steps:
     - name: Setup compiler