Cucumber update 19.0.0

[github-actions[bot]]

[19.0.0] - 2021-05-15

Added

• [JavaScript] Experimental support for Markdown. See MARKDOWN_WITH_GHERKIN.md (#1209 [aslakhellesoy])

Changed

• [DotNet] Replaced Utf8Json with source-embedded TinyJson. (#511 [gasparnagy])

• Update Dutch translation of the "Rule" keyword. (#1513 [OrhanTozan])

• Update Russian translation of the "Scenario Outline" keyword. (#1499 [hkosova])

• Update Hungarian translation of the "Rule" keyword. (#1518 [gasparnagy])

• Upgrade to messages 16.0.0

Removed

• [Elixir] The package was not released - it needs to be updated to pass acceptance tests.
• [Perl] The package was not released - it needs to be updated to pass acceptance tests.

Fixed

• [Perl] Reinstate Perl 5.10.1 compatibility. (#1495 #1494 [ehuelsmann])

• [DotNet] Fixed .NET Gherkin compatibility with other Gherkin implementations. (#511 [gasparnagy])

[ciaranmcnulty]

Some translation changes, but a lot of our tests are failing - I'll investigate whether it's a significant AST change or just something in how we're mapping the JSON

[ciaranmcnulty]

Checked upstream and Cucumber now provides default values (e.g. empty strings) in lots of places rather than omitting strings, so its just null vs '' type stuff

This will need changes in the mappings used in the test suite