[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at e1d4ca0 [InstCombine] matchRotate - add support for matching general funnel shifts with constant shift amounts (PR46896)
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   e1d4ca0..a4e2722  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to a4e27220c2a1046616556b8aadb0ae8f5e0255be.
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!