Use uuid in Map Matching response

[danpaz]

Soon the Map Matching API will start returning a uuid field for all successful map match requests.

Once this field is returned for all profiles we should start using it in MapboxJava and remove the placeholder here

mapbox-java/services-matching/src/main/java/com/mapbox/api/matching/v5/MatchingResponseFactory.java

Line 73 in aa126fc

.requestUuid(PLACEHOLDER_UUID)

In the meantime, while we transition to including the uuid in all responses, we could consider adding optional parsing of the uuid field that falls back gracefully to the placeholder string. This could be useful for responses like NoMatch or NoRoute that don't return a uuid either.

/cc @Guardiola31337

[1ec5]

mapbox/mapbox-directions-swift#457 tracks the equivalent change on iOS. That change can happen safely even if not all the profiles are returning UUIDs yet.