Error “The authenticity of host 'github.com' can't be established. RSA key fingerprint ”

Question

I use my project at work, but I would like to work with him from home as I can log into my home machine to work with my project.

However, from home, I see the following

Answer 1

You should simply be able to answer 'yes', which will update your ~/.ssh/known_hosts file.

After that, you can use a GitHub SSH URL (provided you have generated the SSH public/private keys, and registered the public one to your GitHub profile)

Note: the ssh key generation should use the base64 old PEM format (option -m PEM), rather than the new current 70 chars OpenSSH one.
See "What is the correct format for private key in Credentials":

ssh-keygen -m PEM -t rsa -P "" -f afile

That or you can switch to an HTTPS URL.