[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 3fe01f0 [llvm-readobj] - Simplify the code that creates dumpers. NFCI.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   3fe01f0..9300ca5  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 9300ca541164b80efb7d42dc45219b5d8e05de68.
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!