[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at bbe5099 [compiler-rt][cmake] Simplify COMPILER_RT_HAS_VERSION_SCRIPT tests
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   bbe5099..3da6a97  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 3da6a974db86ba7d1f9a17a1e229daeade52a038.
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!