Bump xunit from 2.6.6 to 2.7.1 in /src/Prefab/templates/prefab

Bumps [xunit](https://github.com/xunit/xunit) from 2.6.6 to 2.7.1.
- [Commits](xunit/xunit@2.6.6...2.7.1)

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

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

src/Prefab/templates/prefab/src/Prefab.Tests/Prefab.Tests.csproj

@@ -9,7 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
-    <PackageReference Include="xunit" Version="2.6.6" />
+    <PackageReference Include="xunit" Version="2.7.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.5.7">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>