tendermint::PrivateKey doesn't derive Copy or Clone

[zbuc]

The tendermint::PrivateKey enum doesn't derive Copy or Clone, but the underlying ed25519_consensus::SigningKey contained by the enum supports both.

I was able to work around this by cloning the inner value:

let cloned_key = tendermint::PrivateKey::Ed25519(
   other_key.ed25519_signing_key().unwrap().clone(),
);

but it'd be nicer to be able to Copy/Clone the type directly if possible.

[tony-iqlusion]

Would strongly recommend explicit Clone over Copy. You don't want to indiscriminately make copies of private keys.

[zbuc]

Good point, we'll update ed25519-consensus as well