[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 3504acc [ARM] Don't mark vctp as having sideeffects
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   3504acc..2f3862e  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 2f3862eb9f21e8a0d48505637fefe6e5e295c18c.
CMake Error at CMakeLists.txt:6 (message):
  Your CMake version is 3.7.1.  The minimum version of CMake required to
  build LLVM is now 3.13.4.


-- Configuring incomplete, errors occurred!