Bump Shouldly and System.CodeDom (#329)

Bumps [Shouldly](https://github.com/shouldly/shouldly) and [System.CodeDom](https://github.com/dotnet/runtime). These dependencies needed to be updated together.

Updates `Shouldly` from 4.2.1 to 4.3.0
- [Release notes](https://github.com/shouldly/shouldly/releases)
- [Changelog](https://github.com/shouldly/shouldly/blob/master/BREAKING%20CHANGES.txt)
- [Commits](shouldly/shouldly@4.2.1...4.3.0)

Updates `System.CodeDom` from 9.0.0 to 6.0.0
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v9.0.0...v6.0.0)

---
updated-dependencies:
- dependency-name: Shouldly
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: System.CodeDom
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Directory.Packages.props

@@ -15,7 +15,7 @@
     <PackageVersion Include="Microsoft.IO.Redist" Version="6.1.0" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageVersion Include="Microsoft.VisualStudio.Setup.Configuration.Interop" Version="3.12.2149" />
-    <PackageVersion Include="Shouldly" Version="4.2.1" />
+    <PackageVersion Include="Shouldly" Version="4.3.0" />
     <PackageVersion Include="System.IO.Compression" Version="4.3.0" />
     <PackageVersion Include="System.Text.Json" Version="$(SystemTextJsonVersion)" />
     <PackageVersion Include="xunit" Version="2.9.3" />