Bump Gradle plugin to 3.4.1

Summary:
This matches the latest stable Android Studio version which will loudly
complain unless you accept this modification.

Reviewed By: danielbuechele

Differential Revision: D15520117

fbshipit-source-id: 81301722d85cbcb07fc1b17b6ce7418d03103874

build.gradle

@@ -9,7 +9,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.4.0'
+        classpath 'com.android.tools.build:gradle:3.4.1'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$KOTLIN_VERSION"
     }
 }