[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 573ade4 [libc][WrapperGen] Replace the C _Noreturn annotation with C++ [[noreturn]].
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   573ade4..062b5c5  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 062b5c598f21c1591b10362219e3c89e934367b0.
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!