Add rustup repository (#1090)

* Add rustup repository

The permissions for the rust-lang/rust repository are out-of-date, and
instead of manually updating them we want to manage the repository
automatically.

* Remove explicit permissions for mods

The mods have org-wide permissions, so we don't need to set them on the
individual repository as well.

Author: jdno

repos/rust-lang/rustup.toml

@@ -0,0 +1,10 @@
+org = "rust-lang"
+name = "rustup"
+description = "The Rust toolchain installer"
+bots = ["rustbot"]
+
+[access.teams]
+rustup = "maintain"
+
+[[branch-protections]]
+pattern = "master"

teams/rustup.toml

@@ -22,3 +22,6 @@ description = "Designing and implementing rustup"
 discord-invite = "https://discord.gg/e6Q3cvu"
 discord-name = "#wg-rustup"
 repo = "https://github.com/rust-lang/rustup"
+
+[[github]]
+orgs = ["rust-lang"]