[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 53fc426 [InstCombine] Add tests for or(shl(x,c1),lshr(y,c2)) patterns that could fold to funnel shifts
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   53fc426..7d07405  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 7d07405761aec8434a0cdb1c5644823a394f7def.
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!