[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at e6c2c9a [lldb] [test] Fix DW_TAG_GNU_call_site-DW_AT_low_pc.s relocation
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   e6c2c9a..4ffa6a2  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 4ffa6a27aca17fe88fa6bdd605b198df6632a570.
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!