This PR partially closes #1404. Namely, it updates the grammar and other
parts of the code to be able to check whether CometBFT respects ABCI
2.0. The only thing missing is to update ADR when this implementation is
accepted.

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---

#### PR checklist

- [ ] Tests written/updated
- [ ] Changelog entry added in `.changelog` (we use
[unclog](https://github.com/informalsystems/unclog) to manage our
changelog)
- [ ] Updated relevant documentation (`docs/` or `spec/`) and code
comments
- [ ] Title follows the [Conventional
Commits](https://www.conventionalcommits.org/en/v1.0.0/) spec

---------

Co-authored-by: nenadmilosevic95 <nenad@informal.systems>
Co-authored-by: Andy Nogueira <me@andynogueira.dev>
Co-authored-by: Daniel <daniel.cason@informal.systems>
(cherry picked from commit 9f02125)