Update test project to .NET 6

[0xced]

Proposed Changes

• Code style update (formatting)
• Refactoring (no functional changes, no api changes)

What is the current behavior?

The test project is using .NET Core 2.2 which is out of support.

What is the new behavior?

The test project is using .NET 6 which is the current LTS version.

Checklist

Please check if your PR fulfills the following requirements:

• [x] Documentation has been added/updated
• [x] Automated Unit / Integration tests for the changes have been added/updated
• [x] Contains NO breaking changes
• [x] Updated the Changelog
• [ ] Associated with an issue