[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 40470eb [libomptarget][NFC] Replace `%ld` with PRId64 for data of type int64_t.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   40470eb..c661691  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to c66169136fe667d653ff40ba4bd9f6047702e93c.
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!