Bump xunit from 2.9.0 to 2.9.1 in /examples/csharp-dotnet

Bumps [xunit](https://github.com/xunit/xunit) from 2.9.0 to 2.9.1.
- [Commits](xunit/xunit@2.9.0...2.9.1)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

examples/csharp-dotnet/tests/HelloWorld/HelloWorld.Test.csproj

@@ -12,7 +12,7 @@
         <PackageReference Include="JunitXml.TestLogger" Version="4.0.254" />
         <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>