test: upgrade docker-compose

Co-authored-by: Rémi Buisson <remi.buisson@traefik.io>

integration/resources/compose/hostresolver.yml

@@ -1,6 +1,13 @@
-server1:
-  image: traefik/whoami
-  labels:
-    - traefik.enable=true
-    - traefik.http.services.service1.loadbalancer.server.port=80
-    - traefik.http.routers.router1.rule=Host("github.com")
+version: "3.8"
+services:
+  server1:
+    image: traefik/whoami
+    labels:
+      traefik.enable: true
+      traefik.http.services.service1.loadbalancer.server.port: 80
+      traefik.http.routers.router1.rule: Host(`github.com`)
+
+networks:
+  default:
+    name: traefik-test-network
+    external: true