Fix schema assigment in PostgresOperator

[eladkal]

When passing schema in PostgresOperator it throws deprecation warning as the hook converts it to database in

airflow/airflow/providers/postgres/hooks/postgres.py

Lines 80 to 87 in 7ab24c7

	if "schema" in kwargs:
	warnings.warn(
	'The "schema" arg has been renamed to "database" as it contained the database name.'
	'Please use "database" to set the database name.',
	AirflowProviderDeprecationWarning,
	stacklevel=2,
	)
	kwargs["database"] = kwargs["schema"]