Median aggregation is not computing the right value #2588

Describe the bug (required)

looking at the aggregation code I notice that the median aggregation function is not computing the correct value:

https://github.com/tannerlinsley/react-table/blob/aa2835766a7a34f70cd6b579628e4f7e820970ab/src/aggregations.js#L52-L68

see also https://en.wikipedia.org/wiki/Median

Provide an example via Codesandbox! (required)
https://codesandbox.io/s/angry-lehmann-kb9vx?file=/src/App.js

Steps To Reproduce (required)
Steps to reproduce the behavior:

1. Go to 'https://codesandbox.io/s/angry-lehmann-kb9vx?file=/src/App.js
2. Click on "group by status"
3. Compare median values of different groups

Expected behavior (Recommended)
I would expect that these two median values are equal