Change log for DB2_DB

Date	Changes
2024-09-25	Enhancement: - Mapped "System" and "Subsystem" to "additional.fields".
2024-09-19	Enhancement: - Modified date block to parse timestamp correctly.
2024-06-27	Enhancement: - Modified date block to handle new pattern of timestamps. - Added support for new pattern of timestamp.
2024-06-04	Enhancement: - Added a Grok pattern to extract resource_name from the "SQL" field and mapped it to "target.resource.name".
2024-02-26	Enhancement: - Added support for new date formats. - Aligned "principal.ip" and "principal.asset.ip" mapping. - Aligned "principal.hostname" and "principal.asset.hostname" mapping. - Aligned "target.hostname" and "target.asset.hostname" mapping.
2023-12-16	Enhancement - Mapped "ConnectionType" to "principal.process.pid". - Mapped "plan" to "principal.resource.name". - Mapped "SSID" to "network.session_id". - Mapped "CorrelationUser" to "intermediary.user.userid". - Mapped "SQL" to "principal.process.command_line".
2023-10-30	Enhancement - Parsed new format of JSON logs. - Mapped the following additional fields: - Mapped "AuthenticatedUser" to "principal.user.userid". - Mapped "SQL" to "target.resource.attribute.labels". - Parsed "date" and "time" field.
2022-05-04	Bug-fix - Added condition check for the presence of fields 'objtyp' and 'obj' before they get mapped. - Parsed the logs failing during Validation API testing.