[skip-ci] v0.20.0: whats-new for release (#5905)
[skip-ci] v0.20.0: whats-new for release (#5905)

Co-authored-by: Tom Nicholas <05cb38613d10a7afcca03fe0ccd71dd2bb31b95c@users.noreply.github.com>
jhamman/xarray,markelg/xray,pydata/xarray,pydata/xarray,markelg/xray,jhamman/xarray,pydata/xarray,jhamman/xarray,markelg/xray