[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 26c1ced [sanitizer] Use __atomic_load/store() built-ins for generic 32-bit targets
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   26c1ced..05e4f7b  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 05e4f7bde95a83192b84f8bb1e6bcd416343154c.
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!