[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 7c37b82 [SyntaxTree][Synthesis] Add support for Tree.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   7c37b82..f5ab5b2  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to f5ab5b20fb2aae5567e6c50cc642ff63eb2146d4.
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!