[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 4637daa Revert D84264 "[SCCP] Directly remove non-feasible edges" & 5db5b4bc4394ca247c9eb665e03b851848aa2fbf
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   4637daa..4589dd9  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 4589dd924dfc43c846652b85825e291af0d7428a.
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!