[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 310f62b [InstCombine] narrowFunnelShift - fold trunc/zext or(shl(a,x),lshr(b,sub(bw,x))) -> fshl(a,b,x) (PR35155)
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   310f62b..b481e00  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to b481e00bf4de31eeb20b95f83b1eae3dcdb4b79c.
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!