Add script for generating upgrade tx specs

[teddyknox]

Description

Adds a set of scripts that make it easy to generate specifications for upgrade/proxy update transactions. Tests

I manually compared the result of this script to previous specifications for upgrade/proxy update transactions, given the same input.

Additional context

Used to generate #672.

[teddyknox]

@emhane as a test? Or what would be the purpose?

[emhane]

@emhane as a test? Or what would be the purpose?

for creating new specs when needed and, yes, for not relying on manual test to check its validity

[tynes]

I would love to merge this but ideally it uses uv instead of pip

[teddyknox]

@geoknee I've updated it to use uv.

[geoknee]

@teddyknox check out https://github.com/ethereum-optimism/specs/pull/778 for a few more pointers.