Hotfix: Return correct exit code when tests fail

[michalholasek]

🚀 Why this change?

Currently, Dredd returns wrong exit code (O) when test(s) fail (should return 1). This change fixes the problem.

📝 Related issues and Pull Requests

Resolves #818.

✅ What didn't I forget?

• To write docs - N/A
• To write tests - N/A
• To put Conventional Changelog prefixes in front of all my commits and run npm run lint

[honzajavorek]

👍 we will continue investigating the problem and we'll follow up with a test etc., but this fixes the issue for now.

[honzajavorek]

Coverage decreased (-0.09%)

This is correct ⬆️ It's hotfix without tests.