git pull 报错The authenticity of h

The authenticity of host 'github.com (192.30.255.112)' can't be established.
RSA key fingerprint is SHA256:xxx.
Are you sure you want to continue connecting (yes/no)? 

原因：known_hosts里面少一个ssh。或者ssh有改动需要更新。
注意：known_hosts可以有多个host的ssh，企业git一个，个人git一个。