Update README.md (#7940)

Add Acando Company to list "Companies/Projects using Swagger Codegen"

Author: densanki

README.md

@@ -747,6 +747,7 @@ Please refer to this [page](https://github.com/swagger-api/swagger-codegen/blob/
 Companies/Projects using Swagger Codegen
 ----------------------------------------
 Here are some companies/projects using Swagger Codegen in production. To add your company/project to the list, please visit [README.md](https://github.com/swagger-api/swagger-codegen/blob/master/README.md) and click on the icon to edit the page.
+- [Acando](https://www.acando.de/)
 - [Accengage](https://www.accengage.com/)
 - [Accruent](https://www.accruent.com/)
 - [Activehours](https://www.activehours.com/)