[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at fce035e [NFC][compiler-rt] Factor out __mulo[sdt]i4 implementations to .inc file
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   fce035e..45344cf  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 45344cf7ac5b848f77825ffa37b0cb3b69b9b07b.
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!