Change log for ZSCALER_CASB

Date Changes
2024-03-05 Enhancement:
- Mapped "event.fileid", "event.intcollabnames", "event.extownername", "event.extcollabnames" to "additional.fields".
2024-01-29 Enhancement:
- Added "gsubs" function to handle invalid escape character, "," in "filesource".
- Added "gsubs" function to handle invalid escape character in "filename".
2023-12-21 Enhancement:
- Added gsubs to handle invalid characters for unparsed JSON logs.
2023-09-30 Enhancement:
- Mapped "event.login" to "principal.user.userid". If not available, set "principal.user.userid" to "n/a".
- Added "on_error" check for "date" filter as "event.lastmodtime" which is an optional parameter.
2022-08-16 Newly created parser