[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 99a93c3 [NFC][Asan] Rename internal enum value.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   99a93c3..0ac8133  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 0ac81333ebc3d75f3c8dfe0ecc5a506c8ef480d7.
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!