[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 2b8ad6b [WebAssembly] Don't depend on the flags set by handleTargetFeatures in initFeatureMap.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   2b8ad6b..5c1fe4e  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 5c1fe4e20f887286baac6989943a0875e12834fe.
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!