upgrade versions of android target, compile sdk and support-core-utils

android/build.gradle

 apply plugin: 'com.android.library'
 
-def DEFAULT_COMPILE_SDK_VERSION             = 26
-def DEFAULT_BUILD_TOOLS_VERSION             = "25.0.2"
-def DEFAULT_TARGET_SDK_VERSION              = 26
+def DEFAULT_COMPILE_SDK_VERSION             = 27
+def DEFAULT_BUILD_TOOLS_VERSION             = "27.0.3"
+def DEFAULT_TARGET_SDK_VERSION              = 27
 def DEFAULT_GOOGLE_PLAY_SERVICES_VERSION    = "12.+"
 
 android {
@@ -29,6 +29,5 @@ dependencies {
     compile "com.google.firebase:firebase-core:$googlePlayServicesVersion"
     compile "com.google.firebase:firebase-messaging:$googlePlayServicesVersion"
     compile 'me.leolin:ShortcutBadger:1.1.17@aar'
-    compile "com.android.support:support-core-utils:26.1.0"
+    compile "com.android.support:support-core-utils:27.1.1"
 }
-