Pin CI runner labels

Author: zayenz

.github/workflows/build.yml

@@ -21,7 +21,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [macos-latest, ubuntu-latest]
+        os: [macos-15, ubuntu-latest]
 
     steps:
     - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0
@@ -91,7 +91,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: macos-latest
+          - os: macos-15
             regenerate_varimp: OFF
           - os: ubuntu-latest
             regenerate_varimp: ON
@@ -808,7 +808,7 @@ jobs:
         }
 
   build-cmake-windows-msys2:
-    runs-on: windows-latest
+    runs-on: windows-2022
 
     steps:
     - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0
@@ -844,7 +844,7 @@ jobs:
         cmake --build "$workspace/build-msys2" --target gecodesearch_static
 
   build-autoconf-windows:
-    runs-on: windows-latest
+    runs-on: windows-2022
 
     steps:
     - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0