build(deps): bump kotlin.version from 1.8.20 to 1.8.21

Bumps `kotlin.version` from 1.8.20 to 1.8.21.

Updates `kotlin-reflect` from 1.8.20 to 1.8.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v1.8.21/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.8.20...v1.8.21)

Updates `kotlin-stdlib-jdk8` from 1.8.20 to 1.8.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v1.8.21/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.8.20...v1.8.21)

Updates `kotlin-stdlib-jdk7` from 1.8.20 to 1.8.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v1.8.21/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.8.20...v1.8.21)

Updates `kotlin-stdlib-common` from 1.8.20 to 1.8.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v1.8.21/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.8.20...v1.8.21)

Updates `kotlin-stdlib` from 1.8.20 to 1.8.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v1.8.21/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.8.20...v1.8.21)

Updates `kotlin-maven-allopen` from 1.8.20 to 1.8.21

Updates `kotlin-maven-noarg` from 1.8.20 to 1.8.21

Updates `kotlin-maven-plugin` from 1.8.20 to 1.8.21

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin:kotlin-reflect
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-stdlib-jdk8
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-stdlib-jdk7
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-stdlib-common
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-stdlib
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-maven-allopen
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-maven-noarg
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

pom.xml

@@ -107,7 +107,7 @@
 
         <!-- Kotlin -->
         <kotlinx-serialization-json.version>1.5.0</kotlinx-serialization-json.version>
-        <kotlin.version>1.8.20</kotlin.version>
+        <kotlin.version>1.8.21</kotlin.version>
         <jackson-module-kotlin.version>2.12.1</jackson-module-kotlin.version>
         <easymock.version>5.1.0</easymock.version>
         <micrometer.version>1.10.6</micrometer.version>