The authenticity of host 'github.com (xxxxxxxxxx)' can't be established.
RSA key fingerprint is xxxxxxxxxxxxxxxxxx.
Are you sure you want to continue connecting (yes/no)?
今天在Win上第一次push，结果...!
于是我默默google了下，大致是Git在SSH连接下，会在第一次验证GitHub服务器的key，所以输入yes再按ENTER键即可。
这个只会在第一次Git中进行push或clone才会出现噢