Changes DateTime types of Model.java to OffsetDatetime

Fixes #48

src/main/java/io/github/amithkoujalgi/ollama4j/core/models/Model.java

@@ -1,6 +1,7 @@
 package io.github.amithkoujalgi.ollama4j.core.models;
 
 import java.time.LocalDateTime;
+import java.time.OffsetDateTime;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.core.JsonProcessingException;
@@ -13,9 +14,9 @@ public class Model {
   private String name;
   private String model;
   @JsonProperty("modified_at")
-  private LocalDateTime modifiedAt;
+  private OffsetDateTime modifiedAt;
   @JsonProperty("expires_at")
-  private LocalDateTime expiresAt;
+  private OffsetDateTime expiresAt;
   private String digest;
   private long size;
   @JsonProperty("details")

src/test/java/io/github/amithkoujalgi/ollama4j/unittests/jackson/TestModelRequestSerialization.java

@@ -0,0 +1,42 @@
+package io.github.amithkoujalgi.ollama4j.unittests.jackson;
+
+import io.github.amithkoujalgi.ollama4j.core.models.Model;
+import org.junit.jupiter.api.Test;
+
+public class TestModelRequestSerialization extends AbstractSerializationTest<Model> {
+
+    @Test
+    public void testDeserializationOfModelResponseWithOffsetTime(){
+        String serializedTestStringWithOffsetTime = "{\n"
+                + "\"name\": \"codellama:13b\",\n"
+                + "\"modified_at\": \"2023-11-04T14:56:49.277302595-07:00\",\n"
+                + "\"size\": 7365960935,\n"
+                + "\"digest\": \"9f438cb9cd581fc025612d27f7c1a6669ff83a8bb0ed86c94fcf4c5440555697\",\n"
+                + "\"details\": {\n"
+                + "\"format\": \"gguf\",\n"
+                + "\"family\": \"llama\",\n"
+                + "\"families\": null,\n"
+                + "\"parameter_size\": \"13B\",\n"
+                + "\"quantization_level\": \"Q4_0\"\n"
+                + "}}";
+        deserialize(serializedTestStringWithOffsetTime,Model.class);
+    }
+
+    @Test
+    public void testDeserializationOfModelResponseWithZuluTime(){
+        String serializedTestStringWithZuluTimezone = "{\n"
+                + "\"name\": \"codellama:13b\",\n"
+                + "\"modified_at\": \"2023-11-04T14:56:49.277302595Z\",\n"
+                + "\"size\": 7365960935,\n"
+                + "\"digest\": \"9f438cb9cd581fc025612d27f7c1a6669ff83a8bb0ed86c94fcf4c5440555697\",\n"
+                + "\"details\": {\n"
+                + "\"format\": \"gguf\",\n"
+                + "\"family\": \"llama\",\n"
+                + "\"families\": null,\n"
+                + "\"parameter_size\": \"13B\",\n"
+                + "\"quantization_level\": \"Q4_0\"\n"
+                + "}}";
+        deserialize(serializedTestStringWithZuluTimezone,Model.class);
+    }
+
+}