[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 7979f24 [test] Fix some unused check prefixes in test/Analysis/CostModel/X86
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   7979f24..9bb2b4f  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 9bb2b4f0aacd14b2a9678f7ccae67ebe3020321d.
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!