[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 1d6a724 [MLIR] Change FunctionType::get() and TupleType::get() to use TypeRange
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   1d6a724..e7af986  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to e7af98680ad52ffc6d308ef63667ac6fb4bb16a7.
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!