Support Both Strings and Slack's Plain Text and Markdown Objects

[raycharius]

Is your feature request related to a problem? Please describe.
Up until now, all of the properties that are plain text or markdown text objects per Slack's API have accepted only strings. And the overall logic was if it can be markdown – it defaults to markdown. This can be problematic as some may desire plain text.

Additionally, it has been impossible to configure the emoji and verbatim properties for these objects.

Describe the solution you'd like
The current approach is nice, as it is not verbose. But the library for those properties, the library needs to support strings, markdown objects, and plain-text objects.

Need to create corresponding builder objects and expose those as exports.

[nivekithan]

Hey, whats the status for this issue ?

If this is issue is not in active development, can I work on it ? most likely I can make an pr on this weekend

[joziahmays]

@raycharius I'd like to second the question above. Have you made any progress on this yet? If not, I'd be more than happy to create a PR.

[karol-traczyk]

Hi Ryan, could share what is the current state of this issue? Any date we can expect version 3.0?