[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at d93287c [scan-build] Supprot relative 'file' in cdb.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
Current branch master is up to date.
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!