Removed deprecated OSX runner (#82)

Author: JohanMabille

.github/workflows/main.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-22.04, ubuntu-24.04, macos-13, macos-14, macos-15]
+        os: [ubuntu-22.04, ubuntu-24.04, macos-14, macos-15]
         xeus_static_dependencies: [0]
         xeus_build_shared_lib: [1]
         include: