[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 82974e0 [X86] Don't disassemble wbinvd with 0xf2 or 0x66 prefix.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   82974e0..15f6bad  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 15f6bad6d74a993e366c8fc93a9c91f213ac6bc3.
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!