[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 751f5c8 Fix LLDB tweak in 62a47e994fcf5b73e29547d26cd9676b30cb69a3
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   751f5c8..f543539  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to f5435399e823746bbe1737b95c853d77a42e1ac3.
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!