Update dependency org.jetbrains.kotlin:kotlin-maven-allopen to v1.8.21

Author: renovate[bot]

pom.xml

@@ -16,7 +16,7 @@
 
     <properties>
         <java.version>1.8</java.version>
-        <kotlin.version>1.6.10</kotlin.version>
+        <kotlin.version>1.8.21</kotlin.version>
     </properties>
 
     <dependencies>