fix: rrule type

resources/ts/lib/recurrence.ts

@@ -103,20 +103,11 @@ export function getCron(
         case CronType.EVERY_YEAR:
             return `0 0 1 ${value.toFixed(0)} *`;
         case CronType.EVERY_N_MONTHS:
-            return new RRule({
-                freq: RRule.MONTHLY,
-                interval: value,
-            }).toString();
+            return `RRULE:FREQ=MONTHLY;INTERVAL=${value.toFixed(0)}`;
         case CronType.EVERY_N_WEEKS:
-            return new RRule({
-                freq: RRule.WEEKLY,
-                interval: value,
-            }).toString();
+            return `RRULE:FREQ=WEEKLY;INTERVAL=${value.toFixed(0)}`;
         case CronType.EVERY_N_DAYS:
-            return new RRule({
-                freq: RRule.DAILY,
-                interval: value,
-            }).toString();
+            return `RRULE:FREQ=DAILY;INTERVAL=${value.toFixed(0)}`;
         case CronType.CUSTOM:
             if (validCron(fallback)) {
                 return fallback;