Update MissionService.java

Author: Juhye0k

src/main/java/avengers/lion/mission/service/MissionService.java

@@ -32,7 +32,7 @@
  */
 public class MissionService {
 
-    private static final double THRESHOLD_METERS = 100.0;
+    private static final double THRESHOLD_METERS = 200.0;
 
     private final MissionRepository missionRepository;
     private final ReviewRepository reviewRepository;