[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 9b58b0c [LLD] Ignore ELF tests when ld.lld defaults to MinGW
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   9b58b0c..ba268d2  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to ba268d2fb09ceabfa03a6499258f973be62d7663.
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!