Simplify release checklist
Simplify release checklist

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