Bump kotlin_version from 1.4.21 to 1.4.30 (#402)

Bumps `kotlin_version` from 1.4.21 to 1.4.30.

Updates `kotlin-gradle-plugin` from 1.4.21 to 1.4.30

Updates `kotlin-stdlib` from 1.4.21 to 1.4.30
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.4.21...v1.4.30)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

build.gradle

@@ -1,5 +1,5 @@
 buildscript {
-  ext.kotlin_version = '1.4.21'
+  ext.kotlin_version = '1.4.30'
   repositories {
     google()
     maven { url 'https://maven.fabric.io/public' }