fix: samples/openapi3/server/petstore/kotlin-springboot/pom.xml to re…

…duce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-8384234
- https://snyk.io/vuln/SNYK-JAVA-ORGJETBRAINSKOTLIN-2393744

samples/openapi3/server/petstore/kotlin-springboot/pom.xml

@@ -6,7 +6,7 @@
     <name>openapi-spring</name>
     <version>1.0.0</version>
     <properties>
-        <kotlin.version>1.3.30</kotlin.version>
+        <kotlin.version>2.1.0</kotlin.version>
 	    <kotlinx-coroutines.version>1.2.0</kotlinx-coroutines.version>
         <jakarta-annotation-version>1.3.5</jakarta-annotation-version>
     </properties>