[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 529ba61 [libcxx] [test] Use error_code::default_error_condition to check errors against the expected codes
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   529ba61..1af3cb5  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 1af3cb5424d578d2c58bc55740075bfc2a0f119b.
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!