cb270eae8e Make transaction::Version field private (jrakibi)
6c69b66b0d Use Version constant (jrakibi)
Pull request description:
This commit addresses #4041 by making the `transaction::Version` field private.
This forces people to either use the associated constants (`Version::ONE/TWO/THREE`) or the `non_standard`/`from_consensus` methods for any other transaction version.
This aligns with our approach to `block::Version`
ACKs for top commit:
tcharding:
ACK cb270eae8e
Kixunil:
ACK cb270eae8e
Tree-SHA512: dcf5b50dfeda04e56fec350acd735dcb7099989b552afce4261d559a8a846c0eb3705369ad635ef9bbbfb2373d203a2c3641178925de6685426aa91245db9a8c
81deddd0a9