Bump Eto.Platform.Gtk from 2.8.2 to 2.8.3

Bumps [Eto.Platform.Gtk](https://github.com/picoe/Eto) from 2.8.2 to 2.8.3.
- [Release notes](https://github.com/picoe/Eto/releases)
- [Commits](picoe/Eto@2.8.2...2.8.3)

---
updated-dependencies:
- dependency-name: Eto.Platform.Gtk
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

GlennGUI/GlennGUI.Gtk/GlennGUI.Gtk.csproj

@@ -11,7 +11,7 @@
     </ItemGroup>
 
     <ItemGroup>
-        <PackageReference Include="Eto.Platform.Gtk" Version="2.8.2" />
+        <PackageReference Include="Eto.Platform.Gtk" Version="2.8.3" />
     </ItemGroup>
 
 </Project>