Add max_children to nested sort

[russcam]

Relates: https://discuss.elastic.co/t/net-client-include-max-children-property-in-nested-sorting/161472

NestedSort is currently missing a MaxChildren property. This should be added.

[NataliyaV]

Thanks, really needed stuff!
Any info when there will be a new release containing it?

[russcam]

It's in NEST 6.8.6 if you're using 6.x. For 7.x, there should be a new package out very soon

[NataliyaV]

It's in NEST 6.8.6 if you're using 6.x. For 7.x, there should be a new package out very soon

Maybe any details about the dates? Just considering if it's reasonable to write by ourselves.
Thank you.

[russcam]

@NataliyaV I'm looking at putting a new 7.x release out today