Bump Shouldly from 4.2.0 to 4.2.1 (#3179)

Bumps [Shouldly](https://github.com/shouldly/shouldly) from 4.2.0 to 4.2.1.
- [Release notes](https://github.com/shouldly/shouldly/releases)
- [Changelog](https://github.com/shouldly/shouldly/blob/master/BREAKING%20CHANGES.txt)
- [Commits](shouldly/shouldly@4.2.0...4.2.1)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Directory.packages.props

@@ -17,7 +17,7 @@
     <PackageVersion Include="Microsoft.Toolkit.MVVM" Version="7.1.2" />
     <PackageVersion Include="Microsoft.Xaml.Behaviors.Wpf" Version="1.1.39" />
     <PackageVersion Include="Newtonsoft.Json" Version="13.0.3" />
-    <PackageVersion Include="Shouldly" Version="4.2.0" />
+    <PackageVersion Include="Shouldly" Version="4.2.1" />
     <PackageVersion Include="ShowMeTheXAML" Version="2.0.0" />
     <PackageVersion Include="ShowMeTheXAML.AvalonEdit" Version="2.0.0" />
     <PackageVersion Include="ShowMeTheXAML.MSBuild" Version="2.0.0" />