[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 105608a [AMDGPU] Added missing gfx1031 cases to CGOpenMPRuntimeGPU.cpp
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   105608a..40470eb  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 40470eb27a5c97b01e89d8825626487b0682abec.
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!