fix typo for homeworks 13 directory

src/homework/13-kubernetes-config/project/docker-compose.yml

@@ -0,0 +1,21 @@
+version: "3.7"
+
+services:
+  frontend:
+    build: ./frontend
+    ports:
+      - "8000:80"
+
+  backend:
+    build: ./backend
+    links:
+      - db
+    ports:
+      - "9000:9000"
+
+  db:
+    image: postgres:13-alpine
+    environment:
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_USER: postgres
+      POSTGRES_DB: news