Clean up tasks

[Integer-Ctrl]

Collection of minor TODOs from already merged PRs to make faster progress

• SHA checksum validation #28 / feature added: --validate checksum flag #44
  • Add --validate-checksum to README.md: Update help prompt
  • Move elif file is not None: retrieval of checksum to separate method
  • Duplicate headers["Accept-Encoding"] = "identity"

[agrim-git-hub]

Hi! Thanks for merging my previous PR. I'd be happy to handle the Add --validate-checksum to README.md item quickly so you don't have to worry about it. Let me know if you'd like me to open a PR for that specific item.

[Integer-Ctrl]

@agrim-git-hub thank you for the interest but I'll tackle this later