[Cashtab] Update utxo-lib to latest version

Summary:
Bitgo has published an updated version of utxo-lib with ecash tx support. This diff implements it.

Unfortunately there is still some more work to be done to make the hashType inclusion part of the library.

Test Plan: npm test

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D13723