* Replace `start_date` by `since`, as `start_date` does not exists in the PagerDuty API https://developer.pagerduty.com/api-reference/reference/REST/openapiv3.json/paths/~1incidents/get , but `since` exists.
* Add `excluded_fields[]` to `valid_params` of class `IncidentsStream()`. This new `excluded_fields[]` is used to exclude `log_entries` and `alerts` fields if they are not needed.
* Add `replication_method` to `valid_params` of class `IncidentsStream()`. This allows to pass `INCREMENTAL` replication method for the `incidents` stream.