[10.0.0 Release] One week to the branch

Hi everyone,

This is just a quick reminder that the upcoming release branch is
scheduled for one week from today: Wednesday, 15 January 2020.

When the branch is created, the trunk version will become 11.0.0.

The full release schedule can be found under "Upcoming Releases" in
the column to the right at https://llvm.org

Thanks,
Hans