[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at a3a2431 [clang] Don't look into <sysroot> for C++ headers if they are found alongside the toolchain
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   a3a2431..3a6bfcf  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 3a6bfcf2f902341bb618c4d5e06b2b10d9f02c72.
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!