[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 65c4898 [gn build] Port 9ca6fc4e095
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   65c4898..d093401  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to d093401a2617d3c46aaed9eeaecf877e3ae1a9f1.
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!