Bump xunit from 2.6.6 to 2.9.1

Bumps [xunit](https://github.com/xunit/xunit) from 2.6.6 to 2.9.1.
- [Commits](xunit/xunit@2.6.6...2.9.1)

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

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

SmokeTest/SmokeTest.csproj

@@ -8,7 +8,7 @@
   <ItemGroup>
     <PackageReference Include="Verify.ICSharpCode.Decompiler" Version="3.4.1" />
     <PackageReference Include="Verify.Xunit" Version="23.0.1" />
-    <PackageReference Include="xunit" Version="2.6.6" />
+    <PackageReference Include="xunit" Version="2.9.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.5.6">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

Tests/Tests.csproj

@@ -7,7 +7,7 @@
   <ItemGroup>
     <PackageReference Include="FodyHelpers" Version="6.8.0" />
     <PackageReference Include="Verify.Xunit" Version="23.0.1" />
-    <PackageReference Include="xunit" Version="2.6.6" />
+    <PackageReference Include="xunit" Version="2.9.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.5.6">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>