[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 5f672fe Reland: Introduce -dot-cfg-mssa option which creates dot-cfg style file with mssa comments included in source
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   5f672fe..777ca48  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 777ca48c9f080ff1cd2d3791b8e23504bda7be40.
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!