feat!: update to protocol 21

[willemneal]

No description provided.

[kalepail]

Are we going to need to create some sort of logic for installing futurenet, testnet and mainnet enabled cli versions or branches?

[willemneal]

@leighmcculloch I remember we discussed something similar, but perhaps we should have different branches that would act as a beta/nightly for testnet and futurenet?

[leighmcculloch]

Are we going to need to create some sort of logic for installing futurenet, testnet and mainnet enabled cli versions or branches?

If you need a version of the CLI that only works on protocol 20, you can install v20 of the CLI. The XDR will always be binary backwards compatible from v21 to v20 so all v20 XDRs should be decodable by v21.

cargo install --locked --version '^20' soroban-cli

I think we could add a version modifier and support multiple versions installed or old behavior, such as:

soroban +20 contract invoke
soroban +21 contract invoke

But that functionality doesn't exist today, and because of the complexity to add something like that we need more information about its usefulness.