[R-SIG-Mac] Please test R 4.0.4 RC

[Simon Urbanek]

Dear macOS useRs,

please test the latest R 4.0.4 RC builds from

https://mac.r-project.org/

especially if you are running macOS Big Sur. The known issues introduced by Big Sur have been fixed, but I cannot replicate nor test the spurious touchbar warning.

Also a reminder to *not* install XQuartz betas even if XQuartz ask you to - they are betas for a reason (=unstable) and break things.

Cheers,
Simon