Bump NSubstitute from 5.3.0 to 6.0.0 - #70

Warning: Code scanning cannot determine the alerts introduced by this pull request, because 4 configurations present on refs/heads/main were not found:

Default setup

• ❓  /language:actions
• ❓  /language:csharp
• ❓  /language:javascript-typescript
• ❓  /language:python

View all branch alerts.