Update dependency NUnit3TestAdapter to v6

Author: renovate[bot]

src/Cody.Core.Tests/Cody.Core.Tests.csproj

@@ -64,7 +64,7 @@
       <Version>4.2.2</Version>
     </PackageReference>
     <PackageReference Include="NUnit3TestAdapter">
-      <Version>4.6.0</Version>
+      <Version>6.1.0</Version>
     </PackageReference>
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />