Another git process seems to be running in this repository, e.g.
an editor opened by 'git commit'. Please make sure all processes
are terminated then try again. If it still fails, a git process
may have crashed in this repository earlier:
remove the file manually to continue.
解决方案:进入项目文件夹下的 .git文件中(显示隐藏文件夹或rm .git/index.lock)删除index文件即可。