[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 238ae4e [SyntaxTree] Add const qualifiers, from [llvm-qualified-auto]
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   238ae4e..59fc867  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 59fc86779038b19cf85f87b51052d468286788f2.
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!