[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 1fa0616 [SCEV] Add more tests using info from loop guards for BTC.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   1fa0616..a51d51a  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to a51d51a0d4d72ab423b11da4c5c877bc6e89a580.
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!