[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at e3b0414 [lldb] Change the xcrun (fallback) logic in GetXcodeSDK
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   e3b0414..7993d61  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 7993d61177c8c6e9aa238e57a684c6cd3db3b571.
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!