[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 2213a35 [Polly] Delete unused lambda capture after 7175cffb2133048018df74c1b49d1d4962ea18f2
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   2213a35..324a15c  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 324a15ceade2dc5ac5b0f106e0127c5c47942614.
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!