message: provide an unwrap free implementation of Clone for Signature
  relates to
diff: @@ -41,7 +41,9 @@ impl cbor_event::de::Deserialize for PublicKey {
  pub struct Signature([u8; SIGNATURE_SIZE]);
  impl Clone for Signature {
  fn clone(&self) -> Self {
  - Self::from_slice(self.as_ref()).unwrap()
  + let mut bytes = [0;SIGNATURE_SIZE];
  + bytes.copy_from_slice(&self.0);
  + Signature(bytes)
  }
  }
  impl Signature {
  