[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 7866b91 [lldb] Fix a crash when the ASTImporter is giving us two Imported callbacks for the same target decl
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   7866b91..8427885  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 8427885e27813c457dccb011f65e8ded74444e31.
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!