[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 8475981 [gn build] Port c7562e77b3a
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   8475981..994fb86  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 994fb86bc2a83b24340b803bde243341dee651fa.
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!