[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 62536fa [test] Make ThinLTO/X86/crash_debuginfo.ll work with -enable-new-pm=1
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   62536fa..2089e76  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 2089e762d00cbfdc8db55fd61f55e2f7efa46f67.
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!