Fix FutureWarning in CFTimeIndex.date_type (#2448)
Fix FutureWarning in CFTimeIndex.date_type (#2448)


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