chore(deps): update dependency org.openapitools:openapi-generator-maven-plugin to v7.15.0

Author: renovate[bot]

extension/client/pom.xml

@@ -16,7 +16,7 @@
   <properties>
     <!-- Do meter coverage -->
     <jacoco.skip>false</jacoco.skip>
-    <openapi-generator-version>7.12.0</openapi-generator-version>
+    <openapi-generator-version>7.15.0</openapi-generator-version>
     <camunda.openapi.package>org.camunda.community.rest.client</camunda.openapi.package>
   </properties>