[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 154860a [lldb] Use config.lldb_src_root in lit_config.load_config (NFC)
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   154860a..834b647  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 834b6470d9f111c355053ecff8bed71bf44a6624.
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!