[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 8427885 Temporairly revert "Thread safety analysis: Consider global variables in scope" & followup
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   8427885..455cce3  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 455cce3e216ba3cac0844b4ee9cf85791c1ac046.
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!