> Dump transaction version as an unsigned integer in RPC/TxToUniv
>
> Consensus-wise we already treat it as an unsigned integer (the
> only rules around it are in CSV/locktime handling), but changing
> the underlying data type means touching consensus code for a
> simple cleanup change, which isn't really worth it.
>
> See-also, https://github.com/rust-bitcoin/rust-bitcoin/pull/299
> Additionally treat Tx.nVersion as unsigned in joinpsbts
>
> This gets its own release note callout, though doesn't appear to
> violate the BIP as the BIP appears to be underspecified. We
> probably want to update BIP 174 to mention how version numbers are
> combined.
This is a backport of core#16525