Bump the default group with 2 updates (#29)

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


Updates `xunit` from 2.7.0 to 2.8.0
- [Commits](xunit/xunit@2.7.0...2.8.0)

Updates `xunit.runner.visualstudio` from 2.5.7 to 2.8.0
- [Release notes](https://github.com/xunit/visualstudio.xunit/releases)
- [Commits](xunit/visualstudio.xunit@2.5.7...2.8.0)

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

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

Directory.Packages.props

@@ -4,7 +4,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
-    <PackageVersion Include="xunit" Version="2.7.0" />
-    <PackageVersion Include="xunit.runner.visualstudio" Version="2.5.7" />
+    <PackageVersion Include="xunit" Version="2.8.0" />
+    <PackageVersion Include="xunit.runner.visualstudio" Version="2.8.0" />
   </ItemGroup>
 </Project>