[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 060a4fc [LoopVersioning] Form dedicated exits for versioned loop to preserve simplify form
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   060a4fc..4c5906c  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 4c5906cffd04202387d2f6b50a47d39c0e4f2c0e.
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!