[Feature]: Cosmovisor: add a command to show current upgrade-info

[freak12techno]

Summary

Would be nice to have a command that shows the content of the current upgrade-info.json.

Problem Definition

Okay so I am maintaining this exporter: https://github.com/QuokkaStake/cosmos-node-exporter, and I want to read the upgrade-info.json, to expose it in case there's an upcoming non-governance upgrade that was added via add-upgrade --upgrade-height.
Problem is, in the app I do not want to hardcode the ~/.appd/data/upgrade-info.json, as it might change and also because I do not want to deal with how Cosmovisor is working internally.
So it'd be nice to have a command that reads this file and dumps its content into stdout, and keep it backwards-compatible, so in case the internal structure would change, I can still call the same command and it'd return the same output.

Proposed Feature

Add a Cosmovisor subcommand (like show-upgrade-info) that does the following:

1. reads the current upgrade-info.json, if it's present
2. puts it into stdout
3. if it doesn't exist, either panic or just display that the upgrade does not exist.

Also, feel free to assign me to this, sounds like something extra easy to do.

[julienrbrt]

As it's a very very small feature that doesn't add any maintenance burden, I'd say why not. A bit overkilled but it's almost a one liner for cosmovisor.

[julienrbrt]

It's a great (starting) issue for someone in the community willing to contribute to the SDK.

[Teyz]

Can I take this issue?

[julienrbrt]

Can I take this issue?

Yes, sure! Thank you

[Teyz]

I don't have permissions to create a new branch and push it :/
@julienrbrt

[julienrbrt]

I don't have permissions to create a new branch and push it :/
@julienrbrt

Hey you should fork the repo and submit a PR