Bump Catel.MVVM from 6.0.3 to 6.0.4 in /src

Bumps [Catel.MVVM](https://github.com/Catel/Catel) from 6.0.3 to 6.0.4.
- [Release notes](https://github.com/Catel/Catel/releases)
- [Changelog](https://github.com/Catel/Catel/blob/develop/doc/release%20steps.txt)
- [Commits](Catel/Catel@6.0.3...6.0.4)

---
updated-dependencies:
- dependency-name: Catel.MVVM
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

src/Orc.SupportPackage.Example/Orc.SupportPackage.Example.csproj

@@ -16,7 +16,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Catel.MVVM" Version="6.0.3" />
+    <PackageReference Include="Catel.MVVM" Version="6.0.4" />
     <PackageReference Include="Catel.Fody" Version="4.9.0" PrivateAssets="all" />
     <PackageReference Include="Fody" Version="6.9.1" PrivateAssets="all">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>