editing: Fix preroateted images

Editing does not work correctly if PNGs or JPEGs are already rotated via
an Exif orientation entry before editing. This needs the glycin-image-rs
1.2.1 loader to work correctly.

Closes #481

build-aux/flatpak/org.gnome.Loupe.Devel.json

@@ -112,8 +112,8 @@
             "sources": [
                 {
                     "type": "archive",
-                    "url": "https://download.gnome.org/sources/glycin/1.2/glycin-1.2.0.tar.xz",
-                    "sha256": "16ab4a48398639ef701c7c3e27a2d31075b30e0dcaf3f1652c907b188f4290d0"
+                    "url": "https://download.gnome.org/sources/glycin/1.2/glycin-1.2.1.tar.xz",
+                    "sha256": "ccc578e9a3e83d0dc1535737d1fda09baa95c7167f5e5ecb15f786654094eed5"
                 }
             ]
         },
@@ -132,4 +132,4 @@
             ]
         }
     ]
-}
+}