닉네임 소문자 변경 처리

src/main/java/com/caliverse/admin/domain/service/DynamoDBService.java

@@ -96,7 +96,7 @@ public class DynamoDBService {
         Map<String, Object> resMap = new HashMap<>();
         Map<String, AttributeValue> key = new HashMap<>();
         key.put("PK", AttributeValue.builder().s("user_nickname_registry#global").build());
-        key.put("SK", AttributeValue.builder().s(primaryKey).build());
+        key.put("SK", AttributeValue.builder().s(primaryKey.toLowerCase(Locale.ENGLISH)).build());
         // GetItem 요청을 만듭니다.
         GetItemRequest getItemRequest = GetItemRequest.builder()
                 .tableName(metaTable)

src/main/java/com/caliverse/admin/domain/service/MailService.java

@@ -30,10 +30,7 @@ import org.springframework.core.io.ResourceLoader;
 import java.net.MalformedURLException;
 import java.nio.file.Path;
 import java.time.LocalDateTime;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 
 @Slf4j
 @Service