Fix: Set RegionOceania to correct route (#71)

This commit corrects the mapping of RegionOceania to the correct
RouteSEA in the `api/constants.go` file. Previously, the mapping was
incorrect, leading to potential routing issues. This fix ensures that
requests for the Oceania region are correctly routed

Author: yunz-dev

api/constants.go

@@ -67,7 +67,7 @@ var (
 		RegionLatinAmericaNorth: RouteAmericas,
 		RegionLatinAmericaSouth: RouteAmericas,
 		RegionNorthAmerica:      RouteAmericas,
-		RegionOceania:           RouteAmericas,
+		RegionOceania:           RouteSEA,
 		RegionPhilippines:       RouteSEA,
 		RegionRussia:            RouteEurope,
 		RegionSingapore:         RouteSEA,