I have a hosted git repository in my own server and my git repo URL looks like this:
ssh://username@example.com/var/git-repo-path
When I am pushing to the server using Git GUI, I get the following warning.

I can still type ‘yes’ and skip this screen. But I want to know how to fix this warning?
I would fix this by deleting the line containing the outdated host key in
~/.ssh/known_hosts. (It looks like the full path on your system isG:\Users\Lenin\.ssh\known_hosts.)Host key checking is a good thing.
If for some reason you really want to disable the checking, you could add this to
~/.ssh/config: