[gnome-sdk-images/gnome-3-26] Upgrade to WebKitGTK+ 2.18.3

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 09dde97f41e2faf3055ef5b46691d79124e35841
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Fri Nov 24 13:22:02 2017 -0600

    Upgrade to WebKitGTK+ 2.18.3

 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 1bf51c9..55708a0 100644
--- a/org.gnome.Sdk.json.in
+++ b/org.gnome.Sdk.json.in
@@ -621,8 +621,8 @@
             "sources": [
                 {
                     "type": "archive",
-                    "url": "https://webkitgtk.org/releases/webkitgtk-2.18.2.tar.xz";,
-                    "sha256": "b14cb3f1b5321b1dc50abcc0445a97f8e2f8813562bca7ce4d2f8069f6fec8e7"
+                    "url": "https://webkitgtk.org/releases/webkitgtk-2.18.3.tar.xz";,
+                    "sha256": "e15420e1616a6f70f321541d467af5ca285bff66b1e0fa68a01df3ccf1b18f9e"
                 },
                 {
                     "type": "patch",