[`hkdf`] the trait bound `Hmac<H>: Clone` is not satisfied

[c410-f3r]

error[E0277]: the trait bound `Hmac<H>: Clone` is not satisfied
   |
21 | impl<H: EagerHash> HmacImpl for Hmac<H> {
   |                                 ^^^^^^^ the trait `Clone` is not implemented for `Hmac<H>`
   |
note: required by a bound in `HmacImpl`
   |
10 | pub trait HmacImpl: Clone + OutputSizeUser {
   |                     ^^^^^ required by this bound in `HmacImpl`

The hmac crate needs a new release to allow hkdf to pull the changes made in RustCrypto/MACs#253.