Update the AUTHORS file

We haven't been updating the AUTHORS file as various people have added
their contributions to the project, so in this commit I'm catching up on
those updates. It's important for both legal and ethical reasons that
everyone gets appropriate credit for their contributions.

I've taken the list of authors from the commit history. The list of
authors in the file is ordered chronologically by their first commit or
first interaction with the project (as far as I'm aware), which seems
consistent with the order that was there before.

Author: diazona

AUTHORS

@@ -1,7 +1,15 @@
 Sebastian Rahlf <[email protected]> (maintainer)
 Muhammad Hallaj Subery <[email protected]>
 Thomas Weißschuh <[email protected]>
+Ulrich Petri <[email protected]>
+Yuya Kusakabe <[email protected]>
+Bruno Oliveira <[email protected]>
 Benjamin Wohlwend <[email protected]>
-Jason R. Coombs
+Jason R. Coombs <[email protected]>
 David Zaslavsky <[email protected]> (maintainer)
 Corey Oordt <[email protected]> (maintainer)
+Kian-Meng Ang <[email protected]>
+Michał Górny <[email protected]>
+Hasan Ramezani <[email protected]>
+Felix Yan <[email protected]>
+Henri Hulski <[email protected]>