[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 4b530f7 [X86][SSE] Use llvm.abs.* vector intrinsics instead of old (deprecated) SSE/AVX intrinsics for combine tests
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   4b530f7..b22910d  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to b22910daab95be1ebc6ab8a74190e38130b0e6ef.
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!