feat: add support for voice messages

[LordOfPolls]

Pull Request Type

• Feature addition
• Bugfix
• Documentation update
• Code refactor
• Tests improvement
• CI/CD pipeline enhancement
• Other: [Replace with a description]

Description

Add support for voice messages

This does not add support for sending voice messages, Discord has made this clear this is not allowed

Changes

• Add message flag for voice messages
• Add new fields to attachments
• Add editable property to messages to help clarify the state of a message

Related Issues

Test Scenarios

Send a voice message from your phone - use a bot to fetch that message (or listen for it) - check the flags and attachments

Python Compatibility

• I've ensured my code works on Python 3.10.x
• I've ensured my code works on Python 3.11.x

Checklist

• I've run the pre-commit code linter over all edited files
• I've tested my changes on supported Python versions
• I've added tests for my code, if applicable
• I've updated / added documentation, where applicable