[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 73811d3 [lldb] Move copying of files into reproducer out of process
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   73811d3..b22e2e4  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to b22e2e4c6e420b78a8a4c307f0cf002f51af9590.
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!