[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 8270f8c [X86] Add broadcast merge test case for PR48215
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   8270f8c..ad0e764  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to ad0e764ead36d5ed87015ea7aa8ba033117b7477.
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!