[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 8eb338a [test] Fix Other/new-pass-manager.ll with has different behaviors whether or not Polly is enabled
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   8eb338a..5d3332b  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 5d3332bc3ce2de80c68f4d63a7204e3f5803523b.
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!