Add self to credits

CREDITS.md

@@ -34,6 +34,7 @@ People are sorted by name so please keep this order.
 * [Nicolas Elie](https://github.com/nicolaselie): [contributions](https://github.com/FreshRSS/FreshRSS/commits?author=nicolaselie)
 * [Nicolas Lœuillet](https://github.com/nicosomb): [contributions](https://github.com/FreshRSS/documentation/commits?author=nicosomb), [Web](http://www.loeuillet.org/)
 * [plopoyop](https://github.com/plopoyop): [contributions](https://github.com/FreshRSS/FreshRSS/commits?author=plopoyop)
+* [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/)
 * [romibi](https://github.com/romibi): [contributions](https://github.com/FreshRSS/FreshRSS/commits/dev?author=romibi)