Bump kotlin_version from 1.3.60 to 1.3.61

Bumps `kotlin_version` from 1.3.60 to 1.3.61.

Updates `kotlin-gradle-plugin` from 1.3.60 to 1.3.61

Updates `kotlin-stdlib-jdk7` from 1.3.60 to 1.3.61
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v1.3.61/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.3.60...v1.3.61)

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

build.gradle

@@ -7,7 +7,7 @@
 import com.github.spotbugs.SpotBugsTask
 
 buildscript {
-    ext.kotlin_version = '1.3.60'
+    ext.kotlin_version = '1.3.61'
     repositories {
         google()
         jcenter()