chore(deps): update dependency xunit to 2.9.1 (#813)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [xunit](https://redirect.github.com/xunit/xunit) | `2.9.0` -> `2.9.1`
|
[![age](https://developer.mend.io/api/mc/badges/age/nuget/xunit/2.9.1?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![adoption](https://developer.mend.io/api/mc/badges/adoption/nuget/xunit/2.9.1?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
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|
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|

---

### Release Notes

<details>
<summary>xunit/xunit (xunit)</summary>

###
[`v2.9.1`](https://redirect.github.com/xunit/xunit/compare/2.9.0...2.9.1)

[Compare
Source](https://redirect.github.com/xunit/xunit/compare/2.9.0...2.9.1)

</details>

---

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test/Directory.Build.props

@@ -11,7 +11,7 @@
     <ItemGroup>
         <PackageReference Include="FluentAssertions" Version="6.12.1" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
-        <PackageReference Include="xunit" Version="2.9.0" />
+        <PackageReference Include="xunit" Version="2.9.1" />
         <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
             <PrivateAssets>all</PrivateAssets>