[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 0628bea Revert "[PM/CC1] Add -f[no-]split-cold-code CC1 option to toggle splitting"
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   0628bea..1e1dd13  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 1e1dd130349a59f1a5ecd6291ab2b6a081f603a6.
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!