[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 0765d78 [X86] vector-sext.ll - replace X32 check prefix with X86. NFC.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   0765d78..c4472f8  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to c4472f8b4cda6a1802cb4543ae2fed94f798ece7.
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!