ci: drop node 18 as end-of-life

Drop node version `18` (codename `Hydrogen`) from the CI workflow as it is no longer supported after 30 April 2025, refer to
https://nodejs.org/en/about/previous-releases#commercial-support
https://nodejs.org/en/blog/release/v18.20.8

Author: huiyifyj

.github/workflows/test.yml

@@ -9,9 +9,9 @@ jobs:
     strategy:
       matrix:
         node-version:
+          - 24
           - 22
           - 20
-          - 18
 
     steps:
       - name: Checkout code