chore(deps): Bump kotlinVersion from 2.0.21 to 2.1.20

Bumps `kotlinVersion` from 2.0.21 to 2.1.20.

Updates `org.jetbrains.kotlin:kotlin-gradle-plugin` from 2.0.21 to 2.1.20
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.0.21...v2.1.20)

Updates `org.jetbrains.kotlin:kotlin-allopen` from 2.0.21 to 2.1.20
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.0.21...v2.1.20)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin:kotlin-gradle-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.jetbrains.kotlin:kotlin-allopen
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

build.gradle

@@ -23,7 +23,7 @@
 
 buildscript {
     ext {
-        kotlinVersion = '2.0.21'
+        kotlinVersion = '2.1.20'
         springBootVersion = '2.6.7'
         graphqlSpringBootStarterVersion = '11.1.0'
     }