missing gems to work with new key encryption type

[novozhenets]

After https://github.com/miloserdow/capistrano-deploy/commit/0d78e2d5f5935584642121fd66199c7119f349b6 I was getting errors about failed authentication via key

net-ssh-7.0.1/lib/net/ssh/authentication/ed[25](https://github.com/novozhenets/trackfolio-backend/runs/7365266070?check_suite_focus=true#step:4:26)519_loader.rb:19:in `raiseUnlessLoaded': OpenSSH keys only supported if ED25519 is available (NotImplementedError)
net-ssh requires the following gems for ed25519 support:
 * ed25519 (>= 1.2, < 2.0)
 * bcrypt_pbkdf (>= 1.0, < 2.0)

Issue is described here https://github.com/net-ssh/net-ssh/issues/565

This should probably be added to README, it took me quite some time to figure this out

[tiagojsag]

I can confirm I had the same problem, and adding both gems to my Gemfile solved the issue