[UPDATE] Kotlin 1.3.31

Author: XinyueZ

build.gradle

@@ -31,7 +31,7 @@ buildscript {
         gradleVersion = '3.4.0'
         gsonVersion = '2.8.2'
         junitVersion = '4.12'
-        kotlinVersion = '1.3.30'
+        kotlinVersion = '1.3.31'
         ktlintVersion = '0.30.0'
         ktxVersion = '1.0.1'
         lifecycleVersion = '2.1.0-alpha04'