add: support for update collections

[sashahilton00]

Change Summary

add: support for update collections

fix: document update returns 200 not 201 code.

PR Checklist

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[sashahilton00]

do you want me to regenerate this from the updated spec before merging?

[kishorenc]

I presumed this was already generated after the changes in https://github.com/typesense/typesense-api-spec/pull/26 -- was it done before?

[sashahilton00]

It was, I didn't see the spec was out of date until after. I'm regenerating now, will squash and rebase

[sashahilton00]

@kishorenc done