fix: query param ordering respected when creating v2 pacts

[YOU54F]

In creating test for the pact_broker-client rewrite in rust, I need to coerce the Pact files to V2.

This gives me issues with the ordering of certain query string parameters which are expected after the specified participant.

This PR looks to introduce a failing test, and a fix for the issue

[YOU54F]

Hmm still not quite quite

                        .path("/matrix")
                        .query_param("q[][pacticipant]", "Foo")
                        .query_param("q[][version]", "1.2.3")
                        .query_param("q[][pacticipant]", "Bar")
                        .query_param("q[][latest]", "true")
                        .query_param("q[][tag]", "prod")
                        .query_param("latestby", "cvpv");

should return ordering like

query: "q%5B%5D%5Bpacticipant%5D=Foo&q%5B%5D%5Bversion%5D=1.2.3&q%5B%5D%5Bpacticipant%5D=Bar&q%5B%5D%5Blatest%5D=true&q%5B%5D%5Btag%5D=prod&latestby=cvpv"

but returns

"query": "latestby=cvpv&q[][latest]=true&q[][pacticipant]=Foo&q[][tag]=prod&q[][version]=1%2e2%2e3&q[][pacticipant]=Bar"

I'll just overwrite the headers in the pact broker verification task instead

[rholshausen]

The issue is that the queries are stored in a HashMap, which does not guarantee the orders of the entries. If you want to keep the order of the parameters, it will need to use something else. BTreeMap can guarantee the order of the entries, but that is by keeping them in sorted order.

[rholshausen]

See https://stackoverflow.com/questions/30243100/how-do-i-sort-a-map-by-order-of-insertion

BTW, changing the map type would be a breaking change as those structs are used everywhere.

[YOU54F]

Thanks for the additional reference! Ahh well, if no-one else is requesting it, probably not worth the effort.

Will park this for now, as have passing tests with some query string overrides