[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 4a66a1d [InstCombine] allow vectors for masked-add -> xor fold
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   4a66a1d..a461e76  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to a461e76b6f973d3f40944b83a46defba0c136777.
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!