[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 2add7c5 [llvm-ar][Object] Fix detection of need for 64-bit archive symbol tables
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   2add7c5..58d0ef2  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 58d0ef2d0466a893ab400f6a9829057b9d851038.
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!