fixed prod files path

docker-compose.prod.yml

@@ -13,9 +13,8 @@ services:
       - ./backend/pb_data:/pb_data
   htwkalender-frontend:
     build:
-      context: ./code/
-      dockerfile: ./frontend/Dockerfile_prod
-
+      context: ./frontend
+      dockerfile: Dockerfile_prod
   rproxy:
     image: nginx:stable
     volumes: