Update HashService.java

Added missing import statement

starter/cloudstorage/src/main/java/com/udacity/jwdnd/course1/cloudstorage/services/HashService.java

@@ -3,7 +3,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.stereotype.Component;
-
+import org.springframework.stereotype.Service;
 import javax.crypto.SecretKeyFactory;
 import javax.crypto.spec.PBEKeySpec;
 import java.security.NoSuchAlgorithmException;