[gimp] build: libwebp required version was bumped.

[Jehan Pagès <jehanp src gnome org>]

commit 411e550fb7599596f33141d276f3ae9c99a6dbca
Author: Jehan <jehan girinstud io>
Date:   Wed Sep 20 17:02:50 2017 +0200

    build: libwebp required version was bumped.

 build/flatpak/org.gimp.GIMP.json |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/build/flatpak/org.gimp.GIMP.json b/build/flatpak/org.gimp.GIMP.json
index e4b5eb6..3de538e 100644
--- a/build/flatpak/org.gimp.GIMP.json
+++ b/build/flatpak/org.gimp.GIMP.json
@@ -218,8 +218,8 @@
             "sources": [
                 {
                     "type": "archive",
-                    "url": "http://downloads.webmproject.org/releases/webp/libwebp-0.5.2.tar.gz";,
-                    "sha256": "b75310c810b3eda222c77f6d6c26b061240e3d9060095de44b2c1bae291ecdef"
+                    "url": "http://downloads.webmproject.org/releases/webp/libwebp-0.6.0.tar.gz";,
+                    "sha256": "c928119229d4f8f35e20113ffb61f281eda267634a8dc2285af4b0ee27cf2b40"
                 }
             ]
         },