[BE] different file types #3630

Requirements

• [X] Is this a feature request? For questions or discussions use https://lemmy.ml/c/lemmy_support
• [X] Did you check to see if this issue already exists?
• [X] Is this only a feature request? Do not put multiple feature requests in one issue.
• [X] Is this a backend issue? Use the lemmy-ui repo for UI / frontend issues.

Is your proposal related to a problem?

allow for .mp3 .ogg etc. uploads

Describe the solution you'd like.

uploading audio files

Describe alternatives you've considered.

n/a

Additional context

n/a