Bump the dependencies group with 2 updates

Bumps the dependencies group with 2 updates: [org.jetbrains.kotlin.jvm](https://github.com/JetBrains/kotlin) and [org.jetbrains.kotlin.plugin.spring](https://github.com/JetBrains/kotlin).


Updates `org.jetbrains.kotlin.jvm` from 2.0.20 to 2.0.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v2.0.21/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.0.20...v2.0.21)

Updates `org.jetbrains.kotlin.plugin.spring` from 2.0.20 to 2.0.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v2.0.21/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.0.20...v2.0.21)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin.jvm
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dependencies
- dependency-name: org.jetbrains.kotlin.plugin.spring
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dependencies
...

Signed-off-by: dependabot[bot] <[email protected]>

build.gradle.kts

@@ -7,8 +7,8 @@ plugins {
   id("org.springframework.boot") version "3.3.4" apply false
   id("io.spring.dependency-management") version "1.1.6"
   id("com.github.davidmc24.gradle.plugin.avro") version "1.9.1"
-  id("org.jetbrains.kotlin.jvm") version "2.0.20"
-  id("org.jetbrains.kotlin.plugin.spring") version "2.0.20"
+  id("org.jetbrains.kotlin.jvm") version "2.0.21"
+  id("org.jetbrains.kotlin.plugin.spring") version "2.0.21"
   id("org.jlleitschuh.gradle.ktlint") version "12.1.1"
 }