[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 84ce6b9 [lldb] Fix building with GCC 7. NFC.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   84ce6b9..7c026a8  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 7c026a83ee903f00cb0a2827519ccd6f16b6ed03.
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!