Add OpenBSD to the installation docs
Add OpenBSD to the installation docs

bastimeyer/streamlink,streamlink/streamlink,gravyboat/streamlink,gravyboat/streamlink,chhe/streamlink,beardypig/streamlink,wlerin/streamlink,streamlink/streamlink,wlerin/streamlink,bastimeyer/streamlink,melmorabity/streamlink,chhe/streamlink,beardypig/streamlink,melmorabity/streamlink