[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 3897137 [DWARFLinker] Add CompileUnit::getInfo helper that takes a DWARFDie (NFC)
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   3897137..f2e479d  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to f2e479db92452594dfe6aff45ab7841f0a8c69a5.
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!