Change log for ZSCALER_FIREWALL

Date	Changes
2024-04-08	Enhancement: - Added a "gsub" function to remove extra brackets to parse JSON logs. - Mapped "column2" to "principal.user.email_addresses". - Mapped "column35" to "principal.user.userid". - Mapped "column36" to "principal.asset_id". - Mapped "column4" to "additional.fields".
2023-09-12	Enhancement: - Handled unparsed JSON format logs.
2023-03-28	Enhancement - Added some null checks and on_error statements to handle parsing errors. - Added/Modified Grok patterns to parse the logs with CEF format. - Handled the cases when "port", "received_bytes" or "ip" were not in their correct form.
2022-04-29	- Migrated to default parser. - Converted from SDM to UDM.
2022-04-29	- Migrated to default parser. - Converted from SDM to UDM.
2022-04-14	- Added new data element for secure result - Modified mapping for target application, network duration