[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at d273cb6 [gn build] Port 940d0a310dc
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   d273cb6..871d658  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 871d658c9ceb391df34e43d8f7af596c0b8a36df.
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!