Fixes ScheduleInterval spec (#22635)
Fixes ScheduleInterval spec (#22635)

In the schedule interval, the data can actually match more than one schema and the `__type` should decide which type of the interval it actually matches. 

Fixes https://github.com/apache/airflow-client-go/issues/20
lyft/incubator-airflow,Acehaidrey/incubator-airflow,cfei18/incubator-airflow,nathanielvarona/airflow,nathanielvarona/airflow,apache/airflow,apache/airflow,Acehaidrey/incubator-airflow,lyft/incubator-airflow,danielvdende/incubator-airflow,apache/airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,Acehaidrey/incubator-airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,danielvdende/incubator-airflow,cfei18/incubator-airflow,nathanielvarona/airflow,cfei18/incubator-airflow,apache/airflow,cfei18/incubator-airflow,lyft/incubator-airflow,danielvdende/incubator-airflow,cfei18/incubator-airflow,Acehaidrey/incubator-airflow,apache/airflow,Acehaidrey/incubator-airflow,nathanielvarona/airflow,lyft/incubator-airflow,Acehaidrey/incubator-airflow,danielvdende/incubator-airflow,apache/airflow