[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 1922bf1 [lldb] Convert builders to use inheritance (NFC)
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   1922bf1..bd2fa18  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to bd2fa1819b9dc1a863a4b5a8abc540598f56c8f2.
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!