[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 0fa520a Unify the code that updates the ArchSpec after finding a fat binary
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   0fa520a..f81bae9  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to f81bae9ff42f760ed4e3d8f7314a7aee2effe6aa.
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!