Auto merge of #971 - RalfJung:rustup, r=RalfJung
Auto merge of #971 - RalfJung:rustup, r=RalfJung

bump rust even more

Internet in this train isn't good enough to test this... so let's see. ;)

rust-lang/miri,rust-lang/miri,rust-lang/miri,rust-lang/miri,tsion/miri