[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 15a5e86 [lld][WebAssembly] Allow `atomics` feature with unshared memory
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   15a5e86..7db7a35  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 7db7a355453887906d12ffb67df8fbaa5e9e873d.
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!