[Automation] Markdown linting

[dvonthenen]

Proposed changes

Markdown should adhere to known standards. Look into:
ghcr.io/igorshubovych/markdownlint-cli

This is already implemented in Go and needs to be ported over:
deepgram/deepgram-go-sdk#208

Context

Why is this change important to you? How would you use it? How can it benefit other users?

Possible Implementation

Not obligatory, but suggest an idea for implementing addition or change

Other information

Anything else we should know? (e.g. detailed explanation, related issues, links for us to have context, eg. stack overflow, codepen, etc)