New Zealand - Fix Auckland Anniversary Day (#671)

#595
#609

Author: tinohager

src/Nager.Date/HolidayProviders/NewZealandHolidayProvider.cs

@@ -155,7 +155,7 @@ protected override IEnumerable<HolidaySpecification> GetHolidaySpecifications(in
                     EnglishName = "Auckland Anniversary Day",
                     LocalName = "Auckland/Northland Anniversary Day",
                     HolidayTypes = HolidayTypes.Public,
-                    SubdivisionCodes = ["NZ-AUK", "NZ-NTL", "NZ-MWT", "NZ-WKO", "NZ-GIS", "NZ-BOP", "NZ-HKB"],
+                    SubdivisionCodes = ["NZ-AUK", "NZ-NTL", "NZ-WKO", "NZ-GIS", "NZ-BOP"],
                     ObservedRuleSet = closestMondayObservedRuleSet
                 },
                 new HolidaySpecification