[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 2089e76 [libc++] Try to fix cross-loading of lit.local.cfg on Windows
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   2089e76..d981c7b  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to d981c7b7581efc3ef378709042100e75da0185a0.
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!