Bump kotlin.version from 1.7.21 to 1.9.21

Bumps `kotlin.version` from 1.7.21 to 1.9.21.

Updates `org.jetbrains.kotlin:kotlin-bom` from 1.7.21 to 1.9.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.7.21...v1.9.21)

Updates `org.jetbrains.kotlin:kotlin-test-junit5` from 1.7.21 to 1.9.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.7.21...v1.9.21)

Updates `org.jetbrains.kotlin:kotlin-maven-allopen` from 1.7.21 to 1.9.21

Updates `org.jetbrains.kotlin:kotlin-maven-noarg` from 1.7.21 to 1.9.21

Updates `org.jetbrains.kotlin:kotlin-maven-plugin` from 1.7.21 to 1.9.21

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin:kotlin-bom
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.jetbrains.kotlin:kotlin-test-junit5
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.jetbrains.kotlin:kotlin-maven-allopen
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.jetbrains.kotlin:kotlin-maven-noarg
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.jetbrains.kotlin:kotlin-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

pom.xml

@@ -55,7 +55,7 @@
         </sonar.coverage.jacoco.xmlReportPaths>
         <!-- Main -->
         <axon.version>4.9.0</axon.version>
-        <kotlin.version>1.7.21</kotlin.version>
+        <kotlin.version>1.9.21</kotlin.version>
         <!-- Serialization -->
         <jackson-kotlin.version>2.16.0</jackson-kotlin.version>
         <!-- Logging -->