[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 50df5f2 [flang] Fix build with BUILD_SHARED_LIBS=ON and FLANG_BUILD_NEW_DRIVER=ON
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   50df5f2..145e44b  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 145e44bb18853bc9beeac0e64fffd9e6895e71f9.
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!