Release `0.2.0`

[corbanvilla]

Additional contracts ready for production use, along with some improvement of life issues and documentation clarification.

• Reimplement Minter Contracts #221
• Reimplement Finance Contracts #222
• Documentation Updates #224
• Update subpackage package.json values!
• Publish to npm 0.2.0
• Update git-pages or Github Action: Auto-generate documentation #218
• Update contracts or Test Case: Assess consistent versioning #220
• Update Types or Prepublishing Step: Updated Types #223
• Merge into master.
  • Requires some specific rebases. Ask @corbanvilla or @HrikB
• OpenGSN integration ALL Contracts OpenGSN Integration #270
• OpenGSN test compatibility Fixing Contract Tests with Open GSN #280