Remove support for end-of-life Node 18.

Author: DavidAnson

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macos-latest, ubuntu-latest, windows-latest]
-        node-version: [ 18, 20, 22, 23 ]
+        node-version: [ 20, 22, 23 ]
 
     steps:
     - uses: actions/checkout@v4