CIP-0057 | Include Plutus V3

[Unisay]

While the next Plutus Ledger Language version is not yet available on mainnet, its conceivable that one might want to produce a Contract Blueprint for it.

This PR adds v3 to the list of allowed plutusVersion values.

[rphair]

@KtorZ @scarmuega @michaelpj how do you feel about the timing of this change? Would be {useful, misleading} to add this now? If not now, what should this change coincide with exactly?

[rphair]

@Unisay in case the last question isn't settled as a matter of course here, I've added it for initial discussion at our next CIP Editors' meeting (https://hackmd.io/@cip-editors/83). If you have particular experience suggesting this change would be helpful to make now, please come to the meeting if you can & relay it there (and also comment it here).

[Ryun1]

Do the supporting schema's provided with CIP57 also need to also be updated with the new stuff being added via v3? (apologises I am not a plutus expert, so maybe a silly question)

[michaelpj]

I think this seems pretty reasonable. I can see the argument for it being premature, but at this point it seems pretty inevitable that there will be a PlutusV3 ledger language. I guess conceivably we could decide to rename it at the last minute out of spite 😂

[rphair]

OK, in light of #768 (comment) I'll get behind it now. If any reservations come up at the meeting then we can apply these to further reviews. Otherwise if an enthusiastic response we could push it ahead at the meeting.

[Ryun1]

Very small change, no danger of breaking backwards compatibility