In your project root open "build.gradle" and to the "repositories" block add:
maven { url "https://jitpack.io" }
So that your block should look roughly like this:
repositories {
jcenter()
maven { url "https://jitpack.io" }
}
Then, in your module "build.gradle" add this into the dependencies block:
compile 'com.github.HellPie:dev.hellpie.libs.ghupdater:1.0.0'