[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 32a85b2 This is a preliminary version of the test for https://reviews.llvm.org/D88483.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   32a85b2..b8c2d60  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to b8c2d60df522d553a0752772aeffb4b2ad84678e.
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!