feat: Report OS type and version in dredd --version
feat: Report OS type and version in dredd --version

Addressing the simplest item from https://github.com/apiaryio/dredd/issues/625.

vladosaurus/dredd,apiaryio/dredd,cranieri/dredd-extended,cranieri/dredd-extended,apiaryio/dredd,apiaryio/dredd,vladosaurus/dredd