[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 04a0896 Revert "[LoopDeletion] Allows deletion of possibly infinite side-effect free loops"
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   04a0896..8eb338a  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 8eb338a92a4ea300bc3cbdd423500ca8b24f2094.
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!