docker: use the system dns for app containers

src/docker.js

@@ -373,8 +373,6 @@ async function createSubcontainer(app, name, cmd, options) {
     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: {

src/infra_version.js

@@ -6,7 +6,7 @@
 
 exports = module.exports = {
     // a version change recreates all containers with latest docker config
-    'version': '49.7.0',
+    'version': '49.8.0',
 
     // a major version bump in the db containers will trigger the restore logic that uses the db dumps
     // docker inspect --format='{{index .RepoDigests 0}}' $IMAGE to get the sha256