Adding custom gitlab repository in build.sbt

how can i add custom gitlab repository to my build.sbt file? i was able to add a repository without authentication like this:

resolvers ++= Seq(
  "custom" at ""
)

but i don't know how to add private token into request header. for instance, you can do it like this in gradle:

maven {
    url "https://
    name "GitLab"
    credentials(HttpHeaderCredentials) {
        name = 'Private-Token'
        value = ''
    }
    authentication {
        header(HttpHeaderAuthentication)
    }
}