git---如何解决The authenticity of host 'github.com (192.30.255.112)' can't be established.

新生成密钥的时候，git clone或者push的时候，常常会报这样的错误：

The authenticity of host 'github.com (192.30.255.112)' can't be established.
RSA key fingerprint is SHA256:nThbg6kXUpJWGl7E1IGOCspRomTxdCARLviKw6E5SY8.

Google以后明白，少了一个known_hosts文件，原本密钥文件应该是三个，如今是两个，便报了这样的错误，此时选择yes回车以后，即可，同时生成了缺乏了的known_hosts文件：

Are you sure you want to continue connecting (yes/no)? //输入yes，回车