[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at c1d25e9 [TSan][libdispatch] Add interceptors for dispatch_barrier_async_and_wait(), pt. 2
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   c1d25e9..96a979c  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 96a979c0c2950d118da48ac3307e279a41c5a945.
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!