Update to support-v4 21.0.0.
Update to support-v4 21.0.0.

epiphany27/SeriesGuide,0359xiaodong/SeriesGuide,UweTrottmann/SeriesGuide,hoanganhx86/SeriesGuide,artemnikitin/SeriesGuide,UweTrottmann/SeriesGuide,r00t-user/SeriesGuide