[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 8c05c7c [MLIR][SPIRV] Support different function control in (de)serialization
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   8c05c7c..e39d788  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to e39d7884a1f5c5c7136ba2e493e9ac313ccc78ed.
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!