chore(deps): bump org.jetbrains.kotlin:kotlin-maven-allopen

Bumps org.jetbrains.kotlin:kotlin-maven-allopen from 1.8.22 to 1.9.21.

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

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

pom.xml

@@ -35,7 +35,7 @@
         <image.name>ghcr.io/idealo/${project.artifactId}:${project.version}</image.name>
 
         <kotlin.code.style>official</kotlin.code.style>
-        <kotlin.version>1.8.22</kotlin.version>
+        <kotlin.version>1.9.21</kotlin.version>
         <java.version>17</java.version>
 
         <asm.version>9.6</asm.version>