Rename this repository

[yoshuawuyts]

We renamed the initiative to: "the effects initiative", and our Zulip stream is t-lang/effects. We should probably rename this repo to rust-lang/effects-initiative.

cc/ @oli-obk I believe you can do that?

[oli-obk]

Infra needs to do that

[yoshuawuyts]

@rust-lang/infra could you rename this repository to rust-lang/effects-initiative please? 🙏

[jdno]

This is slightly more involved, since we also need to change the configuration in rust-lang/team. I'll prepare a PR so that we can change the name in both the repo and on GitHub simultaneously.