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.