Change log for IPSWITCH_SFTP

Date Changes
2022-09-05 Bug-fix - Updated/Mapped the following fields:-
- Unmapped "src_ip" from "observer.hostname".
- Mapped "logstash.collect.host" to "observer.hostname";
- Changed mapping of "syslog_host" from "target.hostname" to "observer.hostname".
- Changed mapping of "logstash.ingest.host" from "observer.hostname" to "intermediary.hostname".