[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 54205f0 [PowerPC] Allow const pointers for load builtins in altivec.h
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   54205f0..97866b8d master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 97866b8de81ce71cf9ae9e50feb450335b0537a0.
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!