feat: (#18) 웹 썸네일 필드 앞에 s3url을 추가한다

Author: EunjinWoo

src/main/java/com/kusitms/website/domain/project/dto/response/MeetupDetailResponse.java

@@ -86,7 +86,7 @@ public MeetupDetailResponse(MeetupProject meetup, boolean isDetail) {
         this.cardinal = meetup.getCardinal();
         this.name = meetup.getName();
         this.posterUrl = s3Url + meetup.getPosterUrl();
-        this.webThumbnailUrl = meetup.getWebThumbnailUrl();
+        this.webThumbnailUrl = s3Url + meetup.getWebThumbnailUrl();
         this.logoUrl = s3Url + meetup.getLogoUrl();
         this.oneLineIntro = meetup.getOneLineIntro();
         this.instagramUrl = meetup.getInstagramUrl();