Test with GCC 15

Author: gschlager

.github/workflows/test-gcc15.yml

@@ -40,7 +40,7 @@ jobs:
         run: gcc --version
 
       - name: Compile C-extension
-        run: bundle exec rake compile
+        run: CC=14 bundle exec rake compile
 
       - name: Run tests
         run: bundle exec rake test