Update ed25519-dalek due to RUSTSEC-2022-0093

[matthiasbeyer]

Dependabot just issued RUSTSEC-2022-0093 for a project of mine. The issue is resolved in ed25519-dalek starting from 2.0.0 of the crate.
This crate is a transitive dependency of my crate, hence I'm filing this here.

Can you please update your usage of the ed25519-dalek crate?

[Eugeny]

I've bumped the library in #173 - would appreciate if you can look through it.
Do I understand it correctly that the vulnerability is only exploitable if there's an API that allows signing with an incoherent public/secret keypair? In that case, russh isn't directly affected since the keypair is encapsulated in russh_keys::Keypair after loading from a file/buffer