[gnome-sdk-images] Upgrade webkitgtk

[Mathieu Bridon <mbridon src gnome org>]

commit 395b8b1b276738cef130daf3fe3b4be4b8c16d90
Author: Mathieu Bridon <bochecha daitauha fr>
Date:   Tue Jun 13 19:09:38 2017 +0200

    Upgrade webkitgtk

 org.gnome.Sdk.json.in |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/org.gnome.Sdk.json.in b/org.gnome.Sdk.json.in
index c38653e..a3f0df9 100644
--- a/org.gnome.Sdk.json.in
+++ b/org.gnome.Sdk.json.in
@@ -803,8 +803,8 @@
             "sources": [
                 {
                     "type": "archive",
-                    "url": "https://webkitgtk.org/releases/webkitgtk-2.16.2.tar.xz";,
-                    "sha256": "5ef689a202eb2b71141efbe8b7b53288adced90790f9f08df6e0a2ec1809f252"
+                    "url": "https://webkitgtk.org/releases/webkitgtk-2.17.3.tar.xz";,
+                    "sha256": "79f168c30953dbd273f984d3cc85482169e6822fcf7cf0031c86cf8aa1816b35"
                 },
                 {
                     "type": "patch",