[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at acb3b8d [Sanitizers] Fix lint failure with Python 3.6
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   acb3b8d..e704aa4  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to e704aa4f254a26505d4bb9dc38bdee0ff4efa4ba.
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!