[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at f7eac51 [CostModel] remove cost-kind predicate for intrinsics in basic TTI implementation
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   f7eac51..ca59d37  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to ca59d37e0ecc6061f8ca0c80210aec11a4a58e0f.
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!