test: upgrade docker-compose

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

integration/resources/compose/proxy-protocol.yml

@@ -1,7 +1,14 @@
-haproxy:
-  image: haproxy:2.2
-  volumes:
-    - ../haproxy/haproxy.cfg:/usr/local/etc/haproxy/haproxy.cfg
+version: "3.8"
+services:
+  haproxy:
+    image: haproxy:2.2
+    volumes:
+      - ./resources/haproxy/haproxy.cfg:/usr/local/etc/haproxy/haproxy.cfg
 
-whoami:
-  image: traefik/whoami
+  whoami:
+    image: traefik/whoami
+
+networks:
+  default:
+    name: traefik-test-network
+    external: true