Gradle cleanup

sshauthentication-api/build.gradle

@@ -1,17 +1,6 @@
 apply plugin: 'com.android.library'
 apply plugin: 'bintray-release' // must be applied after your artifact generating plugin (eg. java / com.android.library)
 
-buildscript {
-    repositories {
-        jcenter()
-        google()
-    }
-    dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.3'
-        classpath 'com.novoda:bintray-release:0.8.0'
-    }
-}
-
 android {
     if (project.hasProperty('rootProject.ext.compileSdkVersion')) {
         compileSdkVersion rootProject.ext.compileSdkVersion