chore: Add setup-fortran to use the same version of gcc everywhere

.github/workflows/wheels.yaml

@@ -21,10 +21,17 @@ jobs:
       matrix:
         # macos-13 is an intel runner, macos-14 is apple silicon
         os: [ubuntu-latest, windows-latest, macos-13, macos-14]
+        toolchain: [{compiler: gcc, version: 12}]
 
     steps:
       - uses: actions/checkout@v4
 
+      - uses: fortran-lang/setup-fortran@v1
+        id: setup-fortran
+        with:
+          compiler: ${{ matrix.toolchain.compiler }}
+          version: ${{ matrix.toolchain.version }}
+
       - name: Set up QEMU
         if: runner.os == 'Linux'
         uses: docker/setup-qemu-action@v3
@@ -38,7 +45,6 @@ jobs:
           # configure cibuildwheel to build native archs ('auto'), and some
           # emulated ones
           CIBW_ARCHS_LINUX: auto aarch64
-          CIBW_BEFORE_ALL_MACOS: alias gfortran=gfortran-12
 
       - uses: actions/upload-artifact@v4
         with: