Change log for MIMECAST_MAIL

Date Changes
2025-02-06 Enhancement:
- Changed mapping of "filename_for_malachite" from "target.process.file.full_path" to "principal.resource.name".
- Changed mapping of "fileName" from "principal.process.file.full_path" to "target.process.file.full_path".
2025-01-23 Enhancement:
- Mapped "md5" to "target.file.md5".
- Changed mapping of "filename_for_malachite" from "principal.resource.name" to "target.process.file.full_path".
- Mapped "urlCategory" to "principal.url_metadata.categories".
- Mapped "credentialTheft" to "security_result.detection_fields".
- Mapped "reason" to "security_result.summary".
2024-11-13 Enhancement:
- Mapped "URL" to "principal.url".
2024-08-05 Enhancement:
- Mapped "sourceIp" to "principal.ip" and "principal.asset.ip".
- Mapped "url" to "principal.url".
- Mapped "msgid" to "network.email.mail_id".
- Mapped "subject" to "network.email.subject".
- Mapped "senderDomain", "AttNames", and "AttCnt" to "security_result.detection_fields".
2023-03-31 Enhancement:
- Mapped "filename_for_malachite" to "principal.resource.name".
- Mapped "fileName" to "principal.process.file.full_path".
- Mapped "sha256" to "target.file.sha256".
- Mapped "sha1" to "target.file.sha1".
- Added conditional check for "aCode".