[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at a64e858 [IR][FIX] Intrinsics - don't apply default willreturn if IntrNoReturn is specified
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   a64e858..45d785e  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 45d785e22b2c940e6203eceda979e2b2bca57b29.
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!