Bump xunit.runner.visualstudio from 2.5.8 to 2.8.1 (#101)

Bumps [xunit.runner.visualstudio](https://github.com/xunit/visualstudio.xunit) from 2.5.8 to 2.8.1.
- [Release notes](https://github.com/xunit/visualstudio.xunit/releases)
- [Commits](xunit/visualstudio.xunit@2.5.8...2.8.1)

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

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

Author: dependabot[bot]

Directory.Packages.props

@@ -14,7 +14,7 @@
     <PackageVersion Include="Microsoft.CodeAnalysis.CSharp.Analyzer.Testing" Version="1.1.1" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
     <PackageVersion Include="xunit" Version="2.8.1" />
-    <PackageVersion Include="xunit.runner.visualstudio" Version="2.5.8" />
+    <PackageVersion Include="xunit.runner.visualstudio" Version="2.8.1" />
     <PackageVersion Include="FluentAssertions" Version="6.12.0" />
     <PackageVersion Include="coverlet.collector" Version="6.0.2" />
   </ItemGroup>