Moving OpenAPI generator version to 7.9.0

Author: karen-avetisyan-mc

tests/pom.xml

@@ -105,7 +105,7 @@
             <plugin>
                 <groupId>org.openapitools</groupId>
                 <artifactId>openapi-generator-maven-plugin</artifactId>
-                <version>6.6.0</version>
+                <version>7.9.0</version>
                 <executions>
                     <execution>
                         <id>openbanking-client-generation</id>