[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 7ac737e [HeaderSearch] Fix processing #import-ed headers multiple times with modules enabled.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   7ac737e..5257a60  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 5257a60ee02e5cbecb2f577b27a9c89e92b2f85f.
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!