* Changes version from v0 to default for Min and Max ops.

* Added broadcast option in variadic function.

* Added tests.

* Added test for opset8.

* Undo changes for Mean op.
Co-authored-by: Tomasz Dołbniak <tomasz.dolbniak@intel.com>
Co-authored-by: Scott Cyphers <diyessi@users.noreply.github.com>