[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 9103978 [PowerPC] Add readflm/setflm intrinsics to Clang
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   9103978..e1cd7ca  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to e1cd7cac8a36608616d515b64d12f2e86643970d.
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!