[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at def48b0 [PredicateInfo][SCCP] Remove assertion (PR46814)
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   def48b0..b2ee1cd  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to b2ee1cd2d988e08728d43eabc9613c6771979bf9.
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!