This requires updating a couple serde test vectors -- we are tightening
validation so that some existing serde-serialized PSBTs no longer
deserialize. I believe this is the correct thing to do.
Replace derived Psbt serde implementation with one that conforms to
BIP-174. In human readable serde contexts, serialize to the base64
encoded format, and in binary serde contexts, serialize to the raw
binary format.
The previous derived serde implementation cannot be used in a backward or
forward compatible way in binary formats like bincode, which means that
every field added to the Psbt struct would break serde de/serialization
into binary formats. Instead, this one-time breaking change will fix the
issue going forward.
Downstream users with persisted data in the old serde format should continue
using 0.32.x to create migrations to the new format.
Andrew Poelstra
Daniel Roberts