Add DNS to app containers as well

infra has to be bumped since we removed httpPort and moved to containerIp

src/docker.js

@@ -339,6 +339,8 @@ function createSubcontainer(app, name, cmd, options, callback) {
             if (isAppContainer) {
                 containerOptions.Hostname = app.id;
                 containerOptions.HostConfig.NetworkMode = 'cloudron'; // user defined bridge network
+                containerOptions.HostConfig.Dns = ['172.18.0.1']; // use internal dns
+                containerOptions.HostConfig.DnsSearch = ['.']; // use internal dns
 
                 containerOptions.NetworkingConfig = {
                     EndpointsConfig: {