switch to lumino import

.eslintrc.js

@@ -39,6 +39,7 @@ module.exports = {
     '@typescript-eslint/no-explicit-any': 'off',
     '@typescript-eslint/no-non-null-assertion': 'off',
     '@typescript-eslint/no-namespace': 'off',
+    '@typescript-eslint/interface-name-prefix': 'off',
     '@typescript-eslint/explicit-function-return-type': 'off',
     '@typescript-eslint/ban-ts-comment': ['warn', { 'ts-ignore': true }],
     '@typescript-eslint/ban-types': 'warn',

packages/notebook/src/widget.ts

@@ -19,7 +19,7 @@ import { PanelLayout, Widget } from '@lumino/widgets';
 
 import { h, VirtualDOM } from '@lumino/virtualdom';
 
-import { ElementExt } from '@phosphor/domutils';
+import { ElementExt } from '@lumino/domutils';
 
 import {
   ICellModel,