Remove obsolete compose version field

docker-compose.yml

@@ -1,5 +1,3 @@
-version: '3.8'
-
 services:
   app:
     build: .
@@ -12,8 +10,8 @@ services:
       - .env
     restart: unless-stopped
     healthcheck:
-      test: ["CMD", "curl", "-f", "http://localhost:8000/api/health"]
+      test: ["CMD", "python", "-c", "from urllib.request import urlopen; urlopen('http://localhost:8000/admin/api/health', timeout=5).read()"]
       interval: 30s
       timeout: 10s
       retries: 3
-      start_period: 10s
+      start_period: 10s