Auto merge of #93 - RalfJung:miri, r=Amanieu
Auto merge of #93 - RalfJung:miri, r=Amanieu

miri CI: use latest nightly with Miri

Instead of giving up when the latest nightly has no Miri, install the latest nightly that does have Miri.

rust-lang/hashbrown,rust-lang/hashbrown