fix(cli-test-utils): fix ts declaration

the data written by fs.writeFile should be any

Author: fangbinwei

packages/@vue/cli-test-utils/createJSONServer.d.ts

@@ -3,6 +3,17 @@ import { Application } from 'express'
 declare function createJSONServer(
   /**
    * Either a path to a json file (e.g. 'db.json') or an object in memory
+   *
+   * Default:
+   *{
+   *  'posts': [
+   *    { 'id': 1, 'title': 'json-server', 'author': 'typicode' }
+   *  ],
+   *  'comments': [
+   *    { 'id': 1, 'body': 'some comment', 'postId': 1 }
+   *  ],
+   *  'profile': { 'name': 'typicode' }
+   *}
    */
   data?: string | object,
 ): Application

packages/@vue/cli-test-utils/createTestProject.d.ts

@@ -20,6 +20,7 @@ declare function createTestProject(
    * }
    */
   preset: GeneratorRootOptions,
+  /** `path.resolve(cwd, name)` will be the project's root directory */
   cwd?: string | null,
   /**
    * if init git repo
@@ -35,7 +36,7 @@ declare function createTestProject(
   /** read the content for the file */
   read: (file: string) => Promise<string>
   /** write file to project */
-  write: (file: string, content: string) => Promise<void>
+  write: (file: string, content: any) => Promise<void>
   /** execa command at root path of project  */
   run: (command: string, args?: ReadonlyArray<string>) => execa.ExecaChildProcess
   /** delete the file of project */