We're modern progressive parents and aren't about to tell Vector who it can and can't hang out with. As such, we're now allowing you to specify custom DNS servers in your configs.
The configuration isn't complicated, it's a global array field dns_servers:
dns_servers = ["0.0.0.0:53"]
When dns_servers is set Vector will ignore the system configuration and use
only the list of DNS servers provided.
This change was made available in 0.6.0. You can get this change by downloading the latest stable release.