doc: update AUTHORS list

Update AUTHORS file using tools/update-authors.sh

PR-URL: #1234
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

Author: rvagg

AUTHORS

@@ -728,5 +728,12 @@ Michael Dawson <michael_dawson@ca.ibm.com>
 Ruben Verborgh <ruben@verborgh.org>
 Ken Perkins <ken.perkins@rackspace.com>
 Malte-Thorben Bruns <skenqbx@gmail.com>
+Santiago Gimeno <santiago.gimeno@gmail.com>
+Ali Ijaz Sheikh <ofrobots@google.com>
+FangDun Cai <cfddream@gmail.com>
+Alex Yursha <alexyursha@gmail.com>
+Steven Vercruysse <stcruy@users.noreply.github.com>
+Aleksanteri Negru-Vode <aleksanteri.negru-vode@aalto.fi>
+Mathieu Darse <mattdarse@gmail.com>
 
 # Generated by tools/update-authors.sh