[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 0a59711 [NFC][GVN] Add a (horrible) test for D84181 demonstrating non-NFC'ness
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   0a59711..993c1a3  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 993c1a3219a8ae69f1d700183bf174d75f3815d4.
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!