Bump gradle from 4.1.2 to 4.1.3

Bumps gradle from 4.1.2 to 4.1.3.
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

build.gradle

@@ -7,7 +7,7 @@ buildscript {
     }
     dependencies {
         apply plugin: 'maven'
-        classpath 'com.android.tools.build:gradle:4.1.2'
+        classpath 'com.android.tools.build:gradle:4.1.3'
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files