This pull request introduces a new reference category to the Layrz API models, specifically for pump assets that should only display the most recent exit in their history. The update includes documentation, enum changes, and serialization support for this new category.

New Reference Category for Pump Asset Exit History:

• Added ReferenceCategory.atsShowOnlyLastExit to the ReferenceCategory enum, with documentation explaining its use for limiting pump asset exit history to the most recent record. (lib/src/references/src/category.dart)
• Updated the enum-to-JSON mapping to include the new ATS_SHOW_ONLY_LAST_EXIT value for correct serialization and deserialization. (lib/src/references/references.g.dart)

Versioning and Documentation:

• Bumped the package version to 3.8.17 and updated the CHANGELOG.md to document the new reference category. (pubspec.yaml, CHANGELOG.md) [1] [2]