[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at a07a2c8 Use --use-color in run-clang-tidy.py
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   a07a2c8..cc96a82  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to cc96a822917c1d95312a1fdb24e1fc0d5fc925b5.
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!