Change log for ZSCALER_CASB

Date Changes
2025-06-04 - Updated the parser to handle logs where the 'RESPCODE' raw field has a 'NA' value.
2025-06-04 - Updated the parser to handle logs where the 'RESPCODE' raw field has a 'NA' value.
2025-04-30 - Promoted ZSCALER_CASB Premium parser to default. You can see full details in the parser configuration page - https://cloud.google.com/chronicle/docs/ingestion/default-parsers/ingest-zscaler-logs