[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 6ce5b74 [Attributor][NFC] rerun update_test_checks without --scrub-attributes
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   6ce5b74..5067f4b  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 5067f4b6261c07d5df94bf18407235d83ce33861.
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!