sort_by() to support multiple prioritized keys

[eripa]

Please describe your feature request.

It would be great to have way to impose second, third etc sorting order. See the below example. I.e. first sort all documents on X, but for if the value is the same, use the second key Y to sort within those.

Related to #1024

#1024 (comment)

Describe the solution you'd like
If we have file.yml like:

name: Beta
other: Epsilon
---
name: Alfa
other: Gamma
---
name: Beta
other: Delta

And we run a command:

yq ea '[.] | sort_by(.name, .other) | .[] | splitDoc' file.yaml

it could output

name: Alfa
other: Gamma
---
name: Beta
other: Delta
---
name: Beta
other: Epsilon

Describe alternatives you've considered
Have not tried any other solutions. As far as I know this isn't supported, see: #1024 (comment)

[mikefarah]

Fixed in v4.31.1, see https://mikefarah.gitbook.io/yq/operators/sort#sort-by-multiple-fields

[eripa]

This is awesome, thank you!