[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at d0648568 [XRay] Change mips to use version 2 sled (PC-relative address)
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   d0648568..deb00cf master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to deb00cf0b5abd45e160f1e0ff3e3dcce97b071e5.
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!