feat: add mail_v3 functionality for reply_to_list

[lopezator]

Add reply_to_list functionality. It just implements a feature that is available on api but not yet on the SDK (and should).

Checklist

• [x] I acknowledge that all my contributions will be made under the project's license
• [x] I have made a material change to the repo (functionality, testing, spelling, grammar)
• [x] I have read the Contribution Guidelines and my PR follows them
• [x] I have titled the PR appropriately
• [x] I have updated my branch with the main branch
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I have added the necessary documentation about the functionality in the appropriate .md file
• [x] I have added inline documentation to the code I modified

[lopezator]

Tested empirically sending email using my service and worked fine.

[sarinarw]

bump - would like to have this feature added