Release 0.2.0

Added

• Challenges as a way to organize proposals within a fund.
  • New /challenges endpoint in the API.
  • Another CSV file, passed via --challenges command line option, to use in the csv-data load command.

Changed

• Proposal data now feature a challenge_id field.
• OpenAPI version redesignated as 0.1.1.

Fixed

• Updated the dependency stack in released components to tokio 1.0 and warp 0.3.