[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at c41a18c [CMake] Default ENABLE_X86_RELAX_RELOCATIONS to ON
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   c41a18c..4fdc4d8  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 4fdc4d892b988bb9f2e06c3440971d28d6361722.
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!