Update CREDITS.md (#2152)

* Update CREDITS.md

Added myself (thomas-gt, see #2151).
Thanks.

* alphabetical

CREDITS.md

@@ -61,6 +61,7 @@ People are sorted by name so please keep this order.
 * [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)
 * [Thomas Citharel](https://github.com/tcitworld): [contributions](https://github.com/FreshRSS/FreshRSS/pulls?q=is:pr+author:tomgue), [Web](https://www.tcit.fr/)
+* [thomas-gt](https://github.com/thomas-gt): [contributions](https://github.com/FreshRSS/FreshRSS/pulls?q=is:pr+author:thomas-gt)
 * [tomgue](https://github.com/tomgue): [contributions](https://github.com/FreshRSS/FreshRSS/commits?author=tomgue)
 * [Twilek-de](https://github.com/Twilek-de): [contributions](https://github.com/FreshRSS/FreshRSS/pulls?q=is:pr+author:Twilek-de)
 * [Uncovery](https://github.com/uncovery): [contributions](https://github.com/FreshRSS/FreshRSS/pulls?q=is:pr+author:uncovery)