[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 552c6c2 PR44406: Follow behavior of array bound constant folding in more recent versions of GCC.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   552c6c2..efd02c1  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to efd02c1548ee458d59063f6393e94e972b5c3d50.
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!