[gimp] build: fixing Exiv2 source URL in flatpak manifest.

[Jehan <jehanp src gnome org>]

commit 6d117b257f7a99fb1537293b4b32889129f898ac
Author: Jehan <jehan girinstud io>
Date:   Fri Feb 18 15:56:22 2022 +0100

    build: fixing Exiv2 source URL in flatpak manifest.
    
    The source apparently got changed to using the forge's download section.
    The checksum stayed the same (as checked by myself).

 build/flatpak/org.gimp.GIMP-nightly.json | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/build/flatpak/org.gimp.GIMP-nightly.json b/build/flatpak/org.gimp.GIMP-nightly.json
index b3ad74e550..2bb5437640 100644
--- a/build/flatpak/org.gimp.GIMP-nightly.json
+++ b/build/flatpak/org.gimp.GIMP-nightly.json
@@ -59,13 +59,13 @@
                     "sources": [
                         {
                             "type": "archive",
-                            "url": "https://exiv2.org/builds/exiv2-0.27.5-Source.tar.gz";,
+                            "url": 
"https://github.com/Exiv2/exiv2/releases/download/v0.27.5/exiv2-0.27.5-Source.tar.gz";,
                             "sha256": "35a58618ab236a901ca4928b0ad8b31007ebdc0386d904409d825024e45ea6e2",
                             "x-checker-data": {
                                 "type": "anitya",
                                 "project-id": 769,
                                 "stable-only": true,
-                                "url-template": "https://exiv2.org/builds/exiv2-$version-Source.tar.gz";
+                                "url-template": 
"https://github.com/Exiv2/exiv2/releases/download/v$version/exiv2-$version-Source.tar.gz";
                             }
                         }
                     ]