[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at b4bffdb Revert "PR44685: DebugInfo: Handle address-use-invalid type units referencing non-type units"
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   b4bffdb..2f5f5fe  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 2f5f5febf3e4fa9bc80e8a8f63a99d3e6813c499.
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!