[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 95fad44 [DebugInfo] Avoid an infinite loop with a truncated pre-v5 .debug_str_offsets.dwo.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   95fad44..2e4a20f  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 2e4a20fd7062f65c06b438953de3d340df00b7a7.
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!