[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 18df607 [lit] Don't include tests skipped due to sharding in reports
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   18df607..b1210c0  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to b1210c059d1ef084ecd275ed0ffb8343ac3cdfad.
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!