Add author

Author: stefano-maggiolo

AUTHORS.txt

@@ -28,6 +28,7 @@ Kento Nikaido (aka snukent) <snukent@gmail.com>
 William Pettersson <william.pettersson@gmail.com>
 Ludwig Schmidt <ludwigschmidt2@gmail.com>
 Federico Scrinzi (aka volpino) <fox91@anche.no>
+Konstantin Tretyakov <kt@ut.ee>
 Luca Versari <veluca93@gmail.com>
 Hyungsuk Yoon <youhanmir@gmail.com>
 Kenneth Wong <kenneth@wong.pro>