Bump NUnit3TestAdapter from 5.0.0 to 6.1.0

---
updated-dependencies:
- dependency-name: NUnit3TestAdapter
  dependency-version: 6.1.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

docs/core/testing/snippets/order-unit-tests/csharp/NUnit.TestProject/NUnit.Project.csproj

@@ -9,7 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="NUnit" Version="4.5.0" />
-    <PackageReference Include="NUnit3TestAdapter" Version="5.0.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="6.1.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
   </ItemGroup>