Move model and record classes to records

This will eventually reduce boilerplate and provide a more consistent
experience for users. I am leaving the old getter methods as deprecated
for one major version to give users the ability to upgrade before having
to migrate to the updated accessors. There are other breaking changes,
but these will likely not affect most users.

Author: oschwald

CHANGELOG.md

@@ -4,6 +4,18 @@ CHANGELOG
 5.0.0
 ------------------
 
+* **BREAKING:** All model and record classes have been converted to Java records.
+  This provides a more modern, immutable data model with automatic implementations
+  of `equals()`, `hashCode()`, and `toString()`. The abstract classes
+  `AbstractRecord`, `AbstractNamedRecord`, `AbstractResponse`,
+  `AbstractCountryResponse`, `AbstractCityResponse`, and `IpBaseResponse` have
+  been removed. Record components can be accessed using the new accessor methods
+  (e.g., `city()`, `country()`, `location()`). The traditional getter methods
+  (e.g., `getCity()`, `getCountry()`, `getLocation()`) are still available but
+  have been deprecated and will be removed in version 6.0.0.
+* **BREAKING:** `RepresentedCountry` is now a separate record type instead of
+  extending `Country`. It shares the same fields as `Country` but adds a `type`
+  field.
 * The deprecation notices for IP Risk database support have been removed.
   IP Risk database support will continue to be maintained.
 * **BREAKING:** The deprecated `WebServiceClient.Builder` methods