[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at b03ea05 [libc++] NFC: Minor refactoring in filesystem_test_helper.h to ease readability
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   b03ea05..038d884  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 038d884a50a4e72d3f65a315d28d35bda024cb4a.
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!