Can we make newUpdateRequest() function public?

[AdamGlazerMW]

It'd be awesome to use this module to be able to update the indexes on each sheet, but the privateness of the function which creates updateRequest structs prevents this.

spreadsheet/update_request.go

Line 9 in 41eea14

func newUpdateRequest(spreadsheet *Spreadsheet) (r *updateRequest, err error) {

Since all other methods on updateRequest are public too, it makes little sense to keep its constructor private actually.

Can we make this happen please?