Update dependency xunit to 2.9.3

Author: renovate[bot]

src/UniGetUI.PackageEngine.Serializable.Tests/UniGetUI.PackageEngine.Serializable.Tests.csproj

@@ -9,7 +9,7 @@
     <ItemGroup>
         <PackageReference Include="coverlet.collector" Version="6.0.4"/>
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
-        <PackageReference Include="xunit" Version="2.5.3"/>
+        <PackageReference Include="xunit" Version="2.9.3"/>
         <PackageReference Include="xunit.runner.visualstudio" Version="3.1.3">
           <PrivateAssets>all</PrivateAssets>
           <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>