Bump kotlin_version from 1.8.21 to 2.2.20

Bumps `kotlin_version` from 1.8.21 to 2.2.20.

Updates `org.jetbrains.kotlin:kotlin-gradle-plugin` from 1.8.21 to 2.2.20
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.8.21...v2.2.20)

Updates `org.jetbrains.kotlin:kotlin-stdlib-jdk8` from 1.8.21 to 2.2.20
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.8.21...v2.2.20)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin:kotlin-gradle-plugin
  dependency-version: 2.2.20
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: org.jetbrains.kotlin:kotlin-stdlib-jdk8
  dependency-version: 2.2.20
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

build.gradle

@@ -1,5 +1,5 @@
 buildscript {
-    ext.kotlin_version = '1.8.21'
+    ext.kotlin_version = '2.2.20'
     repositories {
         mavenCentral()
         google()