Update CREDITS.md (#1634)

Added Ramón Cutanda as a contributor of the Spanish language

CREDITS.md

@@ -40,6 +40,7 @@ People are sorted by name so please keep this order.
 * [Paulius Šukys](https://github.com/psukys): [contributions](https://github.com/FreshRSS/FreshRSS/pulls?q=is:pr+author:psukys), [Web](http://sukys.eu)
 * [purexo](https://github.com/purexo): [contributions](https://github.com/FreshRSS/FreshRSS/pulls?q=is:pr+author:purexo), [Web](https://purexo.mom/)
 * [Quentin Dufour](https://github.com/superboum): [contributions](https://github.com/FreshRSS/documentation/commits?author=superboum), [Web](http://quentin.dufour.io/)
+* [Ramón Cutanda](https://github.com/rcutanda): [contributions](https://github.com/FreshRSS/FreshRSS/pulls?q=is:pr+author:rcutanda)
 * [romibi](https://github.com/romibi): [contributions](https://github.com/FreshRSS/FreshRSS/commits/dev?author=romibi)
 * [subic](https://github.com/subic): [contributions](https://github.com/FreshRSS/documentation/commits?author=subic)
 * [Tets42](https://github.com/Tets42): [contributions](https://github.com/FreshRSS/FreshRSS/commits?author=Tets42)