💸 add sponsor note (nlohmann#5063)

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

Author: nlohmann

README.md

@@ -80,6 +80,7 @@ You can sponsor this library at [GitHub Sponsors](https://github.com/sponsors/nl
 
 - [Martti Laine](https://github.com/codeclown)
 - [Paul Harrington](https://github.com/phrrngtn)
+- [Mercedes-Benz Group](https://github.com/mercedes-benz)
 
 ### :label: Named Sponsors