[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 080ca50 [llvm-objdump] - Rewrite malformed-archives.test to use YAML descriptions.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   080ca50..0ed1e1d  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 0ed1e1df402fdb3c9572382be1f873b77d661726.
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!