DOC: remove outdated warning (#2818)
DOC: remove outdated warning (#2818)


shoyer/xarray,jhamman/xarray,pydata/xarray,jhamman/xray,chunweiyuan/xarray,pydata/xarray,markelg/xray,jhamman/xarray,shoyer/xray,pydata/xarray,markelg/xray,xray/xray,jhamman/xarray,markelg/xray,shoyer/xarray