[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 3a2b05f [BPI][NFC] Consolidate code to deal with SCCs under a dedicated data structure.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   3a2b05f..0f62a53  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 0f62a53db64a943972e51d3d58610595d22779fd.
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!