[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 455d5a8 [llvm-readobj/elf] - Refine the code for broken PT_DYNAMIC segment diagnostic.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   455d5a8..8206257  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 8206257cb86b50f266df5988aa2604c836e1c95c.
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!