Move to node 20 (#1879)

It includes some permissions changes and other stability fixes, vscode main is also now on node 20.

pipeline-templates/install-node.yaml

@@ -1,5 +1,5 @@
 steps:
 - task:  UseNode@1
   inputs:
-    version: '18.x'
+    version: '20.x'
   displayName: '⚛️ Install Node.js'