[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at cb3fd71 Reland  rG4fcd1a8e6528:[llvm-exegesis] Add option to check the hardware support for a given feature before benchmarking.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   cb3fd71..6c25816  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 6c25816d7b68e794a04ba0d7659178ab17252637.
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!