added solution with tariff options as enum and map

src/main/java/com/pfefferminzia/petinsurance/animals/Animal.java

@@ -4,7 +4,12 @@ import java.math.BigDecimal;
 import java.time.LocalDate;
 
 public sealed interface Animal permits Dog, Cat, SmallAnimal {
-    
+
     LocalDate birthday();
+
     BigDecimal getBaseInsuranceSum();
+
+    default BigDecimal getPremiumAdjustment() {
+        return BigDecimal.ZERO;
+    }
 }