[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at e1c38dd [CSKY 1/n] Add basic stub or infra of csky backend
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   e1c38dd..5e855f1  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 5e855f1e8056ca0800134469ee82e0ff5ad5af59.
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!