尝试使用composer update.这就是错误中的意思.

Try using composer update. That is what it says in the error.

...You may be getting outdated dependencies. Run update to update them...

更新:

Composer试图找到文件夹app/controllers/admin，它在laravel中不是标准文件夹.您确定此文件夹存在吗?如果没有，您可以尝试从composer.json中删除这些文件夹以及其他自定义文件夹，然后手动添加它们.您还可以创建目录，并保持composer.json不变.

Composer is trying to find the folder app/controllers/admin which is no standard folder in laravel. Are you sure this folder exists? If not, you could try removing these, and other custom folders, from the composer.json, and add them manually. You could also create the directories and leave the composer.json untouched.