Upgrade gradle version

Author: civyshk

build.gradle

@@ -21,9 +21,10 @@ buildscript {
                 url 'https://maven.google.com/'
                 name 'Google'
             }
+            google()
         }
 
         dependencies {
-            classpath 'com.android.tools.build:gradle:3.1.2'
+            classpath 'com.android.tools.build:gradle:3.1.3'
         }
 }