[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 0888eaf [Loop Fusion] Use pred_empty and succ_empty (NFC)
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   0888eaf..aa06951  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to aa0695137791d8e7749dd6be5ea0e6a63bd85854.
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!