[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 1d1515a [X86] Add an isel pattern for (i8 (trunc (i16 (bitconvert (v16i1 X))))) to avoid an extra EXTRACT_SUBREG
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   1d1515a..30967e5  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 30967e51da614fc814f439a925fabbb12f223919.
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!