message: fix(preset-umi): plugin key should be left to cwd/plugin.ts
diff: @@ -2,6 +2,10 @@ import { chalk } from '@umijs/utils';
  import { IApi } from '../types';
  export default (api: IApi) => {
  + api.describe({
  + key: 'command:plugin',
  + });
  +
  api.registerCommand({
  name: 'plugin',
  description: 'inspect umi plugins',
  