[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 76b0f99 [PowerPC] Implement Vector Multiply High/Divide Extended Builtins in LLVM/Clang
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   76b0f99..718e550  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 718e550cd0362c3421accb6e2067b5fdc3eddb17.
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!