Fix dynamic text field type definition

[etiennellipse]

See BotkitConversation.makeOutgoing method.

The text variable must be a string, as it is fed into the mustache renderer here. So the template function must always return a string, or the function will crash later on.

Therefore, the type definition must reflect that. I am getting TypeScript error when returning a string, if I can it to an array, botkit breaks. 😞

[benbrown]

If specified as an array, the function will pick one at random. What breaks if you do this?

[etiennellipse]

@benbrown It works as expected, no problem with that.

The issue is when passing a function with a template, the function must return only one string (and not an array). It is how botkit works, but the type definition does not reflect that correctly. So when using Botkit with a TypeScript project, the type checker screams.

[benbrown]

oh i see, only when applied to the FUNCTIONS. got it! Merging!

[etiennellipse]

Yeah, sorry it was not clear in my PR description now that I read it again.