remove authors and add Bellet Valentine (CNES)

Author: adebardo

AUTHORS.md

@@ -19,7 +19,8 @@ This file keeps track of authors contributions.
 - **Amaury Dehecq** [@adehecq](https://github/adehecq)
 - **Erik Schytt Mannerfelt** [@erikmannerfelt](https://github/erikmannerfelt)
 - **Emmanuel Dubois** [@duboise-cnes](https://github/duboise-cnes) <emmanuel.dubois@cnes.fr>
-- **Alice De Bardonnèche-Richard** [@adebardo](https://github/adebardo) <alice.de-bardonneche-richard@cs-soprasteria.com>
+- **Valentine Bellet** [@Valentine-Bellet](https://github/duboise-cnes) <valentine.bellet@cnes.fr>
+- **Alice de Bardonnèche-Richard** [@adebardo](https://github/adebardo) <alice.de-bardonneche-richard@cs-soprasteria.com>
 
 
 ## Development Lead