Pin CI runner version

Author: JanCBrammer

.github/workflows/ci.yml

@@ -9,7 +9,7 @@ on:
 
 jobs:
   test_glibc_gcc:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     container: gcc:14
 
     steps:
@@ -45,7 +45,7 @@ jobs:
 
 
   test_musl_gcc:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     # We need Python 3.12. That's why we're using alpine:edge.
     # Currently (May 2024) edge is the only Alpine version with Python 3.12.
     # Once edge advances, the Alpine Python version will be bumped and `python -m pip install -e INCHI-1-TEST` will break.