Bump xunit.runner.visualstudio from 2.5.5 to 2.5.6 (#27)

Bumps [xunit.runner.visualstudio](https://github.com/xunit/visualstudio.xunit) from 2.5.5 to 2.5.6.
- [Release notes](https://github.com/xunit/visualstudio.xunit/releases)
- [Commits](xunit/visualstudio.xunit@2.5.5...2.5.6)

---
updated-dependencies:
- dependency-name: xunit.runner.visualstudio
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Joel Verhagen <joel.verhagen@gmail.com>

Directory.Packages.props

@@ -22,6 +22,6 @@
     <PackageVersion Include="NuGet.Versioning" Version="$(NuGetPackageVersion)" />
     <PackageVersion Include="System.CommandLine" Version="2.0.0-beta4.22272.1" />
     <PackageVersion Include="xunit" Version="2.6.4" />
-    <PackageVersion Include="xunit.runner.visualstudio" Version="2.5.5" />
+    <PackageVersion Include="xunit.runner.visualstudio" Version="2.5.6" />
   </ItemGroup>
 </Project>