Auto merge of #4873 - phansch:rustup2, r=eddyb
Auto merge of #4873 - phansch:rustup2, r=eddyb

Rustup to https://github.com/rust-lang/rust/pull/66789

changelog: none

graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust