Update pom.xml

Co-authored-by: Alexander Diehm <alexander.volz@netpioneer.de>

Author: oliemansm

pom.xml

@@ -14,7 +14,7 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <java.version>1.8</java.version>
-        <kotlin.version>1.4.10</kotlin.version>
+        <kotlin.version>1.4.21</kotlin.version>
         <kotlin-coroutines.version>1.4.2</kotlin-coroutines.version>
         <jackson.version>2.10.3</jackson.version>
         <graphql-java.version>16.1</graphql-java.version>