[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at ac06b1a Revert "Switch libLLVMFrontendOpenACC to be a regular CMake library and not a "component""
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   ac06b1a..6ef0711  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 6ef07111a402a87fda096b6b8d7327e4aa89d4d6.
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!