[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at bd5ca4f [scudo][standalone] Skip irrelevant regions during release
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   bd5ca4f..f8454d6  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to f8454d60b829d6cea4b290a43f2978f0f03f294c.
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!