[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 5965fbf [clang-tidy] Fix a crash in bugprone-not-null-terminated-result check when `__STDC_WANT_LIB_EXT1__` was undefined after definition.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   5965fbf..69eb7e3  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 69eb7e36aa3c71997811054bb31d4546b08bfff0.
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!