fix: samples/openapi3/server/petstore/kotlin-springboot-reactive/pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-8230372
- https://snyk.io/vuln/SNYK-JAVA-ORGJETBRAINSKOTLIN-2393744
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-8230364
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-8230365
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-8230366
- https://snyk.io/vuln/SNYK-JAVA-ORGSPRINGFRAMEWORK-8230367

Author: snyk-bot

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

@@ -7,7 +7,7 @@
     <version>1.0.0</version>
     <properties>
         <kotlin.version>1.3.30</kotlin.version>
-	    <kotlinx-coroutines.version>1.2.0</kotlinx-coroutines.version>
+	    <kotlinx-coroutines.version>1.5.0</kotlinx-coroutines.version>
         <jakarta-annotation-version>1.3.5</jakarta-annotation-version>
     </properties>
     <parent>