[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 22808d6 [clang-tidy] Buildbot failure fix for commit rGf5fd7486d6c0
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   22808d6..a5bb247  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to a5bb24758d02e1e42b72561d0ddbd682776d1a4d.
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!