add dictionary-based integer assignment example (GH7043) (#7072)
add dictionary-based integer assignment example (GH7043) (#7072)

Co-authored-by: Illviljan <ae7d6feeeeda16e2fe885966273a27a64c0c2b0a@users.noreply.github.com>
jhamman/xarray,jhamman/xarray,pydata/xarray,pydata/xarray,jhamman/xarray,pydata/xarray