[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 05ae04c [DA][SDA] SyncDependenceAnalysis re-write
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   05ae04c..719ab73  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 719ab7309eb7b7b5d802273b0f1871d6cdb965b1.
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!