feat(termux): GitHub ssh enhancements

[practicalli-johnny]

Adding a local SSH public key to GitHub account

 termux-clipboard-set < $HOME/.ssh/id_rsa.pub && xdg-open https://github.com/settings/keys

Cache the SSH key
Termux doesn't run ssh-agent but does support
SSH key caching using the ssha command

ssh -T [email protected]

This command seems to cache for ssh connection but not for git command.