Update authors list

And remove AUTHORS text file.

.mailmap

@@ -1,2 +1,4 @@
 J. David Ibáñez <jdavid.ibp@gmail.com> <jdavid@itaapy.com>
 Martin Lenders <authmill@datalove.me>
+Richo Healey <richo@psych0tik.net>
+Xavier Delannoy <xavier.delannoy@gmail.com>

AUTHORS

@@ -1,31 +0,0 @@
-The following people have contributed at least one patch to the
-pygit2 project (sorted alphabetically):
-
-Amit Bakshi
-András Veres-Szentkirályi
-Benjamin Kircher
-Bryan O'Sullivan
-Carlos Martín Nieto
-Christian Boos
-Dave Borowitz
-David Versmisse
-Erik van Zijst
-Han-Wen Nienhuys
-Hugh Cole-Baker
-J. David Ibáñez
-Jared Flatow
-John Szakmeister
-Josh Bleecher Snyder
-Julien Miotte
-Martin Lenders
-Nico von Geyso
-Petr Hosek
-Petr Viktorin
-Richo Healey
-Rui Abreu Ferreira
-Sarath Lakshman
-Sebastian Thiel
-Vicent Marti
-Yonggang Luo
-Zoran Zaric
-pistacchio

README.rst

@@ -46,15 +46,21 @@ Authors
 The following people have contributed at least one patch to the
 pygit2 project (sorted alphabetically):
 
+- Alex Chamberlain
 - Amit Bakshi
 - András Veres-Szentkirályi
+- Ben Davis
 - Benjamin Kircher
 - Bryan O'Sullivan
 - Carlos Martín Nieto
 - Christian Boos
 - David Borowitz (*Original author*)
+- David Sanders
 - David Versmisse
+- Eric Davis
+- Eric Schrijver
 - Erik van Zijst
+- Ferengee
 - Han-Wen Nienhuys
 - Hugh Cole-Baker
 - J David Ibáñez (*Current maintainer*)
@@ -67,10 +73,13 @@ pygit2 project (sorted alphabetically):
 - Petr Hosek
 - Petr Viktorin
 - Richo Healey
+- Ridge Kennedy
 - Rui Abreu Ferreira
 - Sarath Lakshman
 - Sebastian Thiel
 - Vicent Marti
+- W Trevor King
+- Xavier Delannoy
 - Yonggang Luo
 - Zoran Zaric
 - pistacchio