Merge pull request #617 from SUPERCILEX/update

Update dependencies

Author: samtstern

auth/build.gradle

@@ -44,16 +44,16 @@ dependencies {
     compile "com.google.firebase:firebase-auth:$firebaseVersion"
     compile "com.google.android.gms:play-services-auth:$firebaseVersion"
 
-    compile 'com.facebook.android:facebook-android-sdk:4.19.0'
-    compile("com.twitter.sdk.android:twitter:2.3.0@aar") { transitive = true }
+    compile 'com.facebook.android:facebook-android-sdk:4.20.0'
+    compile("com.twitter.sdk.android:twitter:2.3.1@aar") { transitive = true }
 
     // The following libraries are needed to prevent incompatibilities with the facebook
     // library when updating com.android.support libraries:
     compile "com.android.support:cardview-v7:$supportLibraryVersion"
 
     testCompile 'junit:junit:4.12'
     //noinspection NewerVersionAvailable, GradleDynamicVersion
-    testCompile 'org.mockito:mockito-core:2.6.+'
+    testCompile 'org.mockito:mockito-core:2.7.+'
     testCompile 'org.robolectric:robolectric:3.2.2'
     // See https://github.com/robolectric/robolectric/issues/1932#issuecomment-219796474
     testCompile 'org.khronos:opengl-api:gl1.1-android-2.1_r1'