feat: Extend API documentation info description

add ors core version and hint on how to render docs for older core versions

openrouteservice/src/main/java/org/heigit/ors/api/OpenApiConfiguration.java

@@ -30,6 +30,8 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import static org.heigit.ors.util.AppInfo.VERSION;
+
 @Configuration
 public class OpenApiConfiguration {
 
@@ -82,7 +84,7 @@ private List<Server> generateServers(ServletContext servletContext) {
     private Info apiInfo() {
         return new Info()
                 .title(SERVICE_NAME)
-                .description("This is the openrouteservice API documentation")
+                .description("This is the openrouteservice API V2 documentation for ORS Core-Version " + VERSION  + ". Documentations for [older Core-Versions](https://github.com/GIScience/openrouteservice-docs/releases) can be rendered with the [Swagger-Editor](https://editor-next.swagger.io/).")
                 .version("2")
                 .contact(apiContact())
                 .license(apiLicence());