🔧 chore: http-only 속성 추가

Author: jiwon1217

backend/src/main/resources/application.yml

@@ -50,3 +50,9 @@ spring:
 file:
   thumbnail-path : images/thumbnail/ # 이후 배포 환경에서는 바꾸면 될 듯
   default-thumbnail-url: /images/thumbnail/default.png
+
+server:
+  servlet:
+    session:
+      cookie:
+        http-only: true