[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at e84c3b2 [libc++] Remove emscripten handling from exception_fallback.ipp
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   e84c3b2..e5dba2d  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to e5dba2d7e5a6ab8266954e13844355d795c8c88b.
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!