[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at a5d6af4 [compiler-rt] Add .clang-tidy with customization to disable readability-identifier-naming
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   a5d6af4..2d65294  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 2d652949be4b772f2c11577621b0ad33052ac844.
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!