2f656f77ba psbt: Use u64 for key type (Tobin C. Harding)
Pull request description:
Currently we use `u8` for key type but it was pointed out that we should be using a `u64` and encoding it as a compact type. The reason our code works now is because the compact type encoding for a `u8` (less than
This breaks the `serde` impl, as shown by changes to the regression tests,
Fix: #2891
ACKs for top commit:
apoelstra:
ACK 2f656f77ba successfully ran local tests
Tree-SHA512: ce5fe46b54cb724a0b0f9f874c037e5b5d344e5d3c380f9cdb3fdb5cbc5e31e4e32c229f5f2f72547823238934f6b0c3640c2c2ce79d98aa57bac509d130cb82