Update for Protocol 21 and latest CLI+stellar-sdk versions

[chadoh]

What problem does your feature solve?

This repository is v old

What would you like to see?

it be up-to-date with latest protocol & library versions

What alternatives are there?

Archive the repository, since the Getting Started guide now has people use https://github.com/stellar/soroban-astro-template with soroban contract init --frontend-template. That repository is probably more useful to focus on, and can more-or-less fulfill the purpose that this one was originally created for.

[pselle]

Going to start working on this!

[Julian-dev28]

Going to start working on this!

hey @pselle how is this coming along?

[pselle]

@Julian-dev28 This was (perhaps unsurprisingly) a bit of bear, but now it's in somewhat a working state. Ideally PR soon? Working with @chadoh as well on this

[janewang]

@Shaptic Please review