[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 832c8a7 [flang][openacc] Fix gang-argument parsing and add validity tests for !$acc loop
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   832c8a7..7b00c80  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 7b00c80888f8fd42b07be0fd23bf3b475b6ae207.
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!