[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at ea4d24c [Syntax] Tablegen Sequence classes. NFC
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   ea4d24c..e3b64eb  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to e3b64eb31c0e9a9f1ac4891b834d71532e545cad.
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!