Release v0.21.0

[BernieWhite]

PR Summary

What's changed since v0.20.0:

• Engine features:
  • Added support for formatting results as markdown. Generate markdown output report #474
    • Use -OutputFormat Markdown or configure Output.Format to output markdown.
    • To format as either detail or summary, use the -As parameter or configure Output.As.
  • Added character case assertion helpers IsLower, and IsUpper. Added character casing assertion helpers #555
    • IsLower checks that all letters in a field value are lowercase.
    • IsUpper checks that all letters in a field value are uppercase.
• General improvements:
  • Numerical strings can be converted with numeric assertion helpers. Convert numerical strings for numeric comparison #550
  • Added outcome Output.Outcome as a configurable option. Add option for setting outcome #552
  • Added help links and default snippets to schemas. Improve schemas to support links to help and default snippets #561
  • Improved rule error reporting by including rule and source location. Not useful error info on a rule with issues #565
• Engineering:
  • Bump Manatee.Json from 13.0.2 to 13.0.3. Bump Manatee.Json from 13.0.2 to 13.0.3 #563
• Bug fixes:
  • Fixed NUnit report reasons should be escaped in markdown. NUnit report reasons converted to markdown #471
  • Fixed reporting of error when rule error is handled. Rule incorrectly reports error when error condition is handled #564
    • Additionally rules can use -ErrorAction Ignore to ignore non-exception errors.
  • Fixed first exception stops other rules from being processed. First exception stops other rules from being processed #566

What's changed since pre-release v0.21.0-B2010010:

• No additional changes.

PR Checklist

• PR has a meaningful title
• Summarized changes
• Change is not breaking
• This PR is ready to merge and is not Work in Progress