Bump kotlin_version from 1.3.31 to 1.3.40

Bumps `kotlin_version` from 1.3.31 to 1.3.40.

Updates `kotlin-gradle-plugin` from 1.3.31 to 1.3.40

Updates `kotlin-stdlib-jdk7` from 1.3.31 to 1.3.40
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v1.3.40/ChangeLog.md)
- [Commits](https://github.com/JetBrains/kotlin/compare/v1.3.31...v1.3.40)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

build.gradle

@@ -7,7 +7,7 @@
 import com.github.spotbugs.SpotBugsTask
 
 buildscript {
-    ext.kotlin_version = '1.3.31'
+    ext.kotlin_version = '1.3.40'
     repositories {
         google()
         jcenter()