KDL 2.0 compliance

[zkat]

KDL 2.0.0-draft.3 is now generally available (kdl-org/kdl#286), and with it, we've decided to encourage existing implementations to start working towards 2.0 support and send feedback and suggestions for anything you might run into, so I'm making this tracking issue. :)

[Exidex]

@zkat What is the story with backwards compatibility. Is the plugin expected to support both? or do we throw away v1 support?

[zkat]

I intend to throw away v1 support going forward, with the expectation that 2.0 will be the only version actually in use, and 1.0 will just be historical

[zkat]

KDL 2.0.0 has been released (https://github.com/kdl-org/kdl/releases/tag/2.0.0)

As far as compatibility goes: some changes were made to v2 not long before release to make it safely unambiguous with v1. If a document happens to parse with both syntaxes, it’s guaranteed to result in the same data regardless of the parser.

Also, it seems like the trend now is for parsers to provide both v2 and v1 support, with optional fallback behavior, since fallback is now fully safe.