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.
解決方案:進入項目文件夾下的 .git文件中(顯示隱藏文件夾或rm .git/index.lock)刪除index文件即可。