[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at bc7df03 Make -fintegrated-cc1 work with cc1as
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   bc7df03..6861d93  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 6861d938e5c946cc7079d9849ef7560d07aa2d80.
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!