Bump xunit.runner.visualstudio from 2.5.5 to 2.5.6

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] <[email protected]>

Author: dependabot[bot]

examples/Xunit.Microsoft.DependencyInjection.ExampleTests/Xunit.Microsoft.DependencyInjection.ExampleTests.csproj

@@ -11,7 +11,7 @@
 	<ItemGroup>
 		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
 		<PackageReference Include="xunit" Version="2.6.4" />
-		<PackageReference Include="xunit.runner.visualstudio" Version="2.5.5">
+		<PackageReference Include="xunit.runner.visualstudio" Version="2.5.6">
 		  <PrivateAssets>all</PrivateAssets>
 		  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
 		</PackageReference>