Add encoding for smart rollup reveal hash

[m-kus]

As specified in https://gitlab.com/tezos/tezos/-/blob/master/src/proto_alpha/lib_protocol/sc_rollup_reveal_hash.ml#L31

[RomarQ]

Thanks :+1:

The change has been added to develop. https://github.com/airgap-it/tezos-rust-sdk/commit/3ecd736daffab0e80c75127c20141dc0831e9204