fatal: Unable to create '/Users/

What did you do?
之前在执行pod更新命令时ctrl + z强制停止，之后再执行 pod update

What did you expect to happen?
更新依赖的pods。

What happened instead?
更新的命令报错，fatal: Unable to create '/Users/xx/.cocoapods/repos/xx-podspecs/.git/index.lock': File exists. 详情如下图。

How to fix
将~/.cococapods/repos/xx/.git/index.lock删除，然后执行pod update