dns_config: should probably look for dns instead

[yeyeoke]

I'm trying to get Headplane to work with the new beta2, but I'm getting this error:

2024-08-21T07:06:07.204Z (ERRO) [CFGX] Recieved invalid configuration file 2024-08-21T07:06:07.205Z (ERRO) [CFGX] The following schema issues were found: 2024-08-21T07:06:07.205Z (ERRO) [CFGX] 'dns_config': Required

It looks like Headplane is expecting dns_config to still be in the config, but it's now called dns:

As a sidenote, I believe that acl_policy_path might also need to be updated to work with later versions, the new format is:

policy: mode: file path: "/etc/headscale/acl.json"