Add support for passing json values to arguments as .txt files

[Christina-Kang]

Changes include:

• Give users the option of passing in a .txt file where they have to pass in a json value for an argument.

Verifed:

• Build and test CI passes
• History and readme updated to reflect changes
• Package version updated according to semantic versioning rules
• Tests modified or added, when applicable
• Updated code owners file, when applicable
• Read the PR checklist

[coveralls]

Coverage increased (+0.7%) to 80.533% when pulling 4125254 on Christina-Kang:accept-json-file into e507825 on Azure:master.

[Christina-Kang]

@samedder Can you review this? Thanks :)

[samedder]

Is this something that Knack cannot support?

[Christina-Kang]

@samedder I don't see support for this in their code or docs.

[samedder]

Rather than us writing custom logic for this, we should contribute to Knack or request them to support this. I don't think this is a feature that should only be added to our CLI.

[Christina-Kang]

I've submitted an issue on their github, but that will take quite a bit of time I suspect. I do not have the time to add to their repo any time soon, and our commands are getting more unmanageable as we add more things for which we can't avoid json easily. We can then remove this when the knack team adds in that feature.

[samedder]

If you've written all the code already for our CLI how much more effort would it be to migrate it back out to knack?

[Christina-Kang]

@samedder I would need to go through all their code and determine what is the best way of adding this without impacting existing items. Probably as a pre-defined built in type, then understand their testing framework which I have not looked at, then update docs, etc. I would need to discuss with their team if that's how they want it to be implemented. It's a non-trivial amount of work to port this. I can add a tracking item and get to it when I have time, but I doubt it will be this month.

[samedder]

@Christina-Kang two things:
1 - This sounds like it needs to be ported from Azure CLI, I'm fine merging this but we should push back and ask Knack to support the same feature set as Azure CLI
2 - Follow the same @ convention to specify file names

[samedder]

Good to merge, but like I said be careful about adding features like this