Add date not allowed to errors

src/main/java/ley/untis/exception/APIRequestException.java

@@ -28,6 +28,8 @@ public class APIRequestException extends Exception {
                 case "too many results":
                     errorType = EnumError.TOOMANYSCHOOLS;
                     break;
+                case "no allowed date":
+                    errorType = EnumError.DATENOTALLOWED;
                 default:
                     errorType = EnumError.UNKNOWN;
                     break;

src/main/java/ley/untis/exception/EnumError.java

@@ -8,6 +8,7 @@ public enum EnumError {
     TOOMANYSCHOOLS,
     NOCONNECTION,
     NOPERMISSION,
-    ELEMENTNOTFOUND
+    ELEMENTNOTFOUND,
+    DATENOTALLOWED
 
 }