build.gradle

allprojects {
    repositories {
        google()
        jcenter()
        ...
        maven {
            url "https://gitlab.com/api/v4/projects/projectid/packages/maven"
            name "GitLab"
            credentials(HttpHeaderCredentials) {
                name = 'Private-Token'
                value = Config.gitLabAccessToken
            }
            authentication {
                header(HttpHeaderAuthentication)
            }
        }
    }
}