Update EffectRandomizer.md

[ncalvin1]

Bump version to 2.0, add pyproject_url, remove legacy flag and the dependency on ChangeUtil, and update the documentation.

[ncalvin1]

Does the old modinfo.json mechanism no longer exist? It's been a while since I tried to update a BL2 mod. Please LMK if I bypassed an automated system.

[apple1417]

Yeah it was removed in favor of this system. You guys couldn't see it but the scanning was an incredibly flaky system, I'd get half a dozen emails a day about spurious build failures.

See https://bl-sdk.github.io/developing/#adding-to-the-mod-db for docs on the new system. One thing I'll note is it's designed to have your pyproject.toml as the single source of truth - so you should be able to get rid of most of the fields in the front matter. Otherwise when you bump version next time, you'd have to come back here to update it on the site, and in general you'd have to keep everything in sync. I think all you have to keep is pyproject_url and redirect_from.