[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at a10a64e [SCEV] Recommit "Use nw flag and symbolic iteration count to sharpen ranges of AddRecs", attempt 2
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   a10a64e..037ef7d  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 037ef7d70c49e76bddf36140cca1606a3023240b.
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!