[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 8df17b4 [test][InstCombine][NewPM] Fix InstCombine tests under NPM
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   8df17b4..3cb8347  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 3cb8347c94a0d8ae1295fa4ae686443f49bc18e8.
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!