fix: require rand feature when generating ecdsa key

[Rjected]

Description

Using libp2p-identity as a crate did not work if default-features is false and ecdsa is included.

The following command also fails:

cargo check --no-default-features --features "ecdsa,ed25519,peerid,secp256k1"

Now, this command works

Notes & open questions

Found this when trying to install enr-cli:

cargo install enr-cli

Bumped the version so it can be bumped in any crates that depend on it such as enr-cli

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• A changelog entry has been made in the appropriate crates