[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 86bd8f8 [CMake] Remove dead FindPythonInterp code
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   86bd8f8..51d30c3  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 51d30c3429fa0f46bf8c0e4a38840952c11be4f9.
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!