Change log for GCP_DNS

Date	Changes
2023-05-12	Enhancement - - Mapped "structuredRdata.ttl" to "dns.answer.ttl". - Mapped "structuredRdata.domainName" to "dns.answer.name". - Mapped "structuredRdata.type" to "dns.answer.type". - Mapped "structuredRdata.class" to "dns.answer.class". - Mapped "structuredRdata.rvalue" to "dns.answer.data".
2023-04-21	Enhancement - - Set "target.resource.attribute.cloud.environment" to "GOOGLE_CLOUD_PLATFORM". - Set "target.resource.name" to the full resource name value.
2022-09-21	Enhancement - _ Mapped the field 'severity' to 'security_result.severity' and 'security_result.severity_details'. - If severity contains critical, alert or emergency, mapped is_alert and is_significant to true.
2022-05-06	Enhancement - Mapped 'jsonPayload.queryType' to 'dns.questions.type' when the type is in the Private Use range, 65280 - 65535.
2022-04-20	- Enhanced the parser to handle all the unparsed raw logs. - Mapped responseCode to network.dns.response_code and additional.fields.key and value.