[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at d3153b5 [X86] Remove a DCI.isBeforeLegalize() call from combineVSelectWithAllOnesOrZeros.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   d3153b5..f4aba9d  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to f4aba9d76c61cc4c87b45e4edb57b1968eb7194c.
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!