gulp#4.0 Did you forget to signal async completion?

异常截图

解决方案：

https://stackoverflow.com/questions/36897877/gulp-error-the-following-tasks-did-not-complete-did-you-forget-to-signal-async

https://blog.csdn.net/qq_41208114/article/details/79109269

// 必须返回一个steam对象
return gulp.src('package.json'); 

// 或者返回一个promise对象
return new Promise((resolve, reject) => {
    console.log('Success'); // Success
    resolve('success')
})