Change log for CISCO_FIREPOWER_FIREWALL

Date Changes
2022-05-05 Enhancement-Moved customer specific to default and fixed incorrectly parsed metadata.event_timestamp.
2022-04-22 Enhancement-Fixed incorrectly parsed metadata.event_timestamp.
2022-04-13 Enhancement- mapped metadata.event_timestamp correctly for some unparsed logs
2022-04-04 Enhancement- Zones, interfaces, policy, user, bytes, Urlcategory and urlreputation fields are mapped.
2022-03-22 Enhancement-IngressZone,EgressZone,Priority,GID,SID,Revision,IntrusionPolicy fields are mapped.