delete upstream workflow

[jeromekelleher]

This is no longer useful and is just a maintenance burden. Delete it, and supporting script infrastructure

[Billyzhang1229]

What about testing against the latest stable releases instead? That might give a cleaner signal, or we could just check around major upstream version bumps rather than running nightly.

[jeromekelleher]

I don't think there's much point. Pinning with a uv lockfile which you update every 6 months will do what's needed.

[Billyzhang1229]

okayyy, I can just remove the upstream workflow as part of my next uv migration.