ci: Refactor DB tests (no-changelog) (#7292)

[DB tests](https://github.com/n8n-io/n8n/actions/runs/6340094467)

.github/docker-compose.yml

@@ -2,15 +2,21 @@ version: '3.9'
 
 services:
   mysql:
-    image: mysql:5.7-debian
+    image: mysql:5.7
     environment:
       - MYSQL_DATABASE=n8n
       - MYSQL_ROOT_PASSWORD=password
     ports:
       - 3306:3306
+    ulimits:
+      nproc: 65535
+      nofile:
+        soft: 26677
+        hard: 46677
 
   postgres:
     image: postgres:11
+    restart: always
     environment:
       - POSTGRES_DB=n8n
       - POSTGRES_USER=root