[gimp] NEWS: add all missing contributors to GIMP 2.9.8.

[Jehan Pagès <jehanp src gnome org>]

commit 6d1dcb505f6c7653bee3c987ca941bbe0ea969a1
Author: Jehan <jehan girinstud io>
Date:   Mon Dec 11 23:32:24 2017 +0100

    NEWS: add all missing contributors to GIMP 2.9.8.
    
    Unless some were not listed as authors of their respective commits, that
    should be the full list.

 NEWS |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/NEWS b/NEWS
index e5a719e..eb71d90 100644
--- a/NEWS
+++ b/NEWS
@@ -156,11 +156,12 @@ Building:
 
 Contributors:
 
-Mario Blättermann, Marco Ciampa, Fran Dieguez, Piotr Drąg,
-Tobias Ellinghaus, Ell, Sveinn í Felli, gogo, Luis Angel Gonzo,
+Mario Blättermann, Hanno Boeck, Joao S O Bueno, Marco Ciampa,
+Fran Dieguez, Piotr Drąg, Tobias Ellinghaus, Ell, Sveinn í Felli,
+gogo, Luis Angel Gonzo, Anders Jonsson, Christian Kirbach,
 Øyvind Kolås, Thomas Manni, Jordi Mas, Balázs Meskó, Lionel N,
 Michael Natterer, Jehan Pagès, Juan Palacios, Alexandre Prokoudine,
-Christopher Rogers, Michael Schumacher, Dimitris Spingos,
+Christopher Rogers, Michael Schumacher, shark0r, Dimitris Spingos,
 Tobias Stoeckmann, Andika Triwidada, Massimo Valentini.
 
 Overview of Changes from GIMP 2.9.4 to GIMP 2.9.6