[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 577f8b15 [Fixed Point] Add codegen for fixed-point shifts.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   577f8b15..e1644a3 master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to e1644a377996565e119aa178f40c567b986a6203.
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!