[vala/0.40] webkit2gtk-4.0: Update to 2.20.1

[Rico Tzschichholz <ricotz src gnome org>]

commit f106b6430bf64622e6f5a55d2d6f754d2e33d49b
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Fri Apr 13 17:56:14 2018 +0200

    webkit2gtk-4.0: Update to 2.20.1

 vapi/webkit2gtk-web-extension-4.0.vapi |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/vapi/webkit2gtk-web-extension-4.0.vapi b/vapi/webkit2gtk-web-extension-4.0.vapi
index 9f225c7..6baed4d 100644
--- a/vapi/webkit2gtk-web-extension-4.0.vapi
+++ b/vapi/webkit2gtk-web-extension-4.0.vapi
@@ -166,7 +166,7 @@ namespace WebKit {
                        [Version (since = "2.18")]
                        public ulong get_length ();
                        [Version (since = "2.18")]
-                       public unowned WebKit.DOM.ClientRect item (ulong index);
+                       public WebKit.DOM.ClientRect item (ulong index);
                        public ulong length { get; }
                }
                [CCode (cheader_filename = "webkit2/webkit-web-extension.h", type_id = 
"webkit_dom_comment_get_type ()")]