bump up maven plugin version

Author: HugoMario

modules/swagger-codegen-maven-plugin/pom.xml

@@ -62,7 +62,7 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-plugin-plugin</artifactId>
-                    <version>3.4</version>
+                    <version>3.6.0</version>
                     <configuration>
                         <skipErrorNoDescriptorsFound>true</skipErrorNoDescriptorsFound>
                     </configuration>