build(deps): bump the xunit group with 2 updates

Bumps the xunit group with 2 updates: [xunit](https://github.com/xunit/xunit) and [xunit.runner.visualstudio](https://github.com/xunit/visualstudio.xunit).


Updates `xunit` from 2.8.0 to 2.8.1
- [Commits](xunit/xunit@2.8.0...2.8.1)

Updates `xunit.runner.visualstudio` from 2.8.0 to 2.8.1
- [Release notes](https://github.com/xunit/visualstudio.xunit/releases)
- [Commits](xunit/visualstudio.xunit@2.8.0...2.8.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Directory.Packages.props

@@ -17,8 +17,8 @@
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
     <PackageVersion Include="NetEvolve.Extensions.XUnit" Version="2.2.12" />
     <PackageVersion Include="Polyfill" Version="5.2.2" />
-    <PackageVersion Include="xunit" Version="2.8.0" />
-    <PackageVersion Include="xunit.runner.visualstudio" Version="2.8.0" />
-    <PackageVersion Update="xunit.runner.visualstudio" Version="2.8.0" Condition=" '$(TargetFramework)' == 'net5.0' Or '$(TargetFramework)' == 'netcoreapp3.1' " />
+    <PackageVersion Include="xunit" Version="2.8.1" />
+    <PackageVersion Include="xunit.runner.visualstudio" Version="2.8.1" />
+    <PackageVersion Update="xunit.runner.visualstudio" Version="2.8.1" Condition=" '$(TargetFramework)' == 'net5.0' Or '$(TargetFramework)' == 'netcoreapp3.1' " />
   </ItemGroup>
 </Project>