adds DNS so the containers can resolve public domain even when resolv.conf was created when a VPN with custom DNS server was active on host

docker-compose.yml

 services:
   adminer:
     container_name: ${PREFIX}-adminer
+    dns:
+      - 1.1.1.1
     hostname: ${PREFIX}-adminer
     image: adminer:4.8.1-standalone
     labels:
       - traefik.http.services.${PREFIX}-adminer.loadbalancer.server.port=8080
   app:
     container_name: ${PREFIX}-app
+    dns:
+      - 1.1.1.1
     environment:
       - PHP_POST_MAX_SIZE=${PHP_POST_MAX_SIZE}
       - PHP_UPLOAD_MAX_FILESIZE=${PHP_UPLOAD_MAX_FILESIZE}
   traefik:
     container_name: ${PREFIX}-traefik
     command: ["--configFile=/etc/traefik/static/traefik.yml"]
+    dns:
+      - 1.1.1.1
     image: traefik:2.5.3
     labels:
       - traefik.enable=true