[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 1d8af68 Revert "[Verifier] Additional check for intrinsic get.active.lane.mask"
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   1d8af68..d2385f6  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to d2385f6d2f1bea4e4913ae3bc3948590e8d9f6c3.
CMake Error at CMakeLists.txt:3 (cmake_minimum_required):
  CMake 3.13.4 or higher is required.  You are running version 3.7.1


-- Configuring incomplete, errors occurred!