[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 91bd9db [DebugInfo] Allow GNU macro extension to be read
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   91bd9db..950f1bf  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 950f1bf976b332eca60267b25bf759e2ad564e0c.
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!