[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 32f2f0d [NFC] Fix banner
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   32f2f0d..0b4fe80  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 0b4fe8086f03294907180007e7de98c80a83b0d7.
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!