Merge pull request #1876 from Urgau/rustbot_compiler-builtins

Enable `rustbot` in `compiler-builtins` repository

Author: Mark-Simulacrum

repos/rust-lang/compiler-builtins.toml

@@ -1,7 +1,7 @@
 org = "rust-lang"
 name = "compiler-builtins"
 description = "Rust implementations of compiler-rt and libm"
-bots = []
+bots = ["rustbot"]
 
 [access.teams]
 crate-maintainers = "maintain"