[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at d110d4aa [InstSimplify] Forbid undef folds in expandBinOp
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   d110d4aa..bebe6a6 master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to bebe6a6449811e877f7eba3f1798ddd1fa83e440.
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!