fix: add set-cookie header for each set-cookie

[hitochan777]

🔗 Linked issue

#725

❓ Type of change

• 📖 Documentation (updates to the documentation, readme or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

📝 Checklist

• I have linked an issue or discussion.
• I have added tests (if possible).
• I have updated the documentation accordingly.

[hitochan777]

@zoey-kaiser I know you are busy, but could you please take some time to review my code?

[zoey-kaiser]

@zoey-kaiser I know you are busy, but could you please take some time to review my code?

@phoenix-ru will do a review today! Then we can move forward. Thank you for your patience 😊

[phoenix-ru]

@hitochan777 Brilliant work! Thanks for a thorough issue documentation in #725 and for providing a reproduction repository, these really helped

Merging your code and we'll do a patch release soon