[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at a52852f [NFC][sanitizer] Reformat some code
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   a52852f..4ec7f7e  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 4ec7f7e45a6c12c6cc2fea36cf15e90ebb1bb6ea.
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!