[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 892ef2e [AMDGPU] More codegen patterns for v2i16/v2f16 build_vector
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   892ef2e..f835779  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to f835779160ec30340676918915526615a07e826e.
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!