[gnome-sdk-images/gnome-3-26] Update to WebKitGTK+ 2.18.6

[Michael Catanzaro <mcatanzaro src gnome org>]

commit ab3dd06471f8dd0cf78984ef96216048005ad2e7
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Wed Jan 24 08:09:14 2018 -0600

    Update to WebKitGTK+ 2.18.6

 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 4af45ac..da888db 100644
--- a/org.gnome.Sdk.json.in
+++ b/org.gnome.Sdk.json.in
@@ -631,8 +631,8 @@
             "sources": [
                 {
                     "type": "archive",
-                    "url": "https://webkitgtk.org/releases/webkitgtk-2.18.5.tar.xz";,
-                    "sha256": "0c6d80cc7eb5d32f8063041fa11a1a6f17a29765c2f69c6bc862cd47c2d539b8"
+                    "url": "https://webkitgtk.org/releases/webkitgtk-2.18.6.tar.xz";,
+                    "sha256": "93912cc2f40f12e452be1ca4babdbdaac0ec4f828d441257a6b06c2963bbac3c"
                 },
                 {
                     "type": "patch",