no need to test vscode on node 18

Author: ndbroadbent

.github/workflows/vscode.yml

@@ -27,7 +27,7 @@ jobs:
           - ubuntu-latest
           - macos-latest
           - windows-latest
-        node-version: [18.x, 20.x]
+        node-version: [20.x]
 
     steps:
       - uses: actions/checkout@v4