[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at a0c2c6a [X86][AVX] Fold CONCAT(HOP(X,Y),HOP(Z,W)) -> HOP(CONCAT(X,Z),CONCAT(Y,W)) for float types
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   a0c2c6a..35bee35  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 35bee3503f4c33d92434a314e49e3e6f4f7419bc.
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!