updated project style guidelines

lib/api/webuntis/queries/getHolidays/getHolidays.dart

@@ -8,7 +8,7 @@ class GetHolidays extends WebuntisApi {
 
   @override
   Future<GetHolidaysResponse> run() async {
-    String rawAnswer = await query(this);
+    var rawAnswer = await query(this);
     return finalize(GetHolidaysResponse.fromJson(jsonDecode(rawAnswer)));
   }
 
@@ -17,12 +17,12 @@ class GetHolidays extends WebuntisApi {
     time = DateTime(time.year, time.month, time.day, 0, 0, 0, 0, 0);
 
     for (var element in holidaysResponse.result) {
-      DateTime start = DateTime.parse(element.startDate.toString());
-      DateTime end = DateTime.parse(element.endDate.toString());
+      var start = DateTime.parse(element.startDate.toString());
+      var end = DateTime.parse(element.endDate.toString());
 
       if(!start.isAfter(time) && !end.isBefore(time)) return element;
     }
     return null;
   }
 
-}
+}