[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at cf36142 [clang] Add missing header guard in <cpuid.h>
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   cf36142..7dcc889  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 7dcc8899174f44b7447bc48a9f2ff27f5458f8b7.
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!