[beta] Backport #84894 to fix beta CI#86092

Merged

bors merged 2 commits intorust-lang:betafrom

JohnTitor:clang-12-beta

Jun 8, 2021

Commits on Jun 7, 2021

CI: Extract LLVM win64 installer directly, using 7z

joshtriplett
authored and
JohnTitor
committed
Update clang to 12.0.0 on Windows and macOS

joshtriplett
authored and
JohnTitor
committed