`groupby_bins` problem in `multidimensional-coords.ipynb`

[smartlixx]

What is your issue?

In multidimensional-coords.ipynb, the groupby_bins operation was on the coordinate xc, but the bins provided were from 0 to 90 and labeled as 'latitude center'. Based on groupby_bins document, the first argument is the variable to group on. I wonder if here it should be groupby_bins("yc") rather than groupby_bins("xc")? Please correct me if my understanding is wrong.

[mathause]

I had a quick look at multidimensional-coords.ipynb and agree - that should be yc. We're happy to take a PR.