Notify when newer versions are available

[tronghn]

The CLI should check for and notify the user when a newer version is available, as these usually have bug fixes and new features. Sometimes, breaking changes to APIs require that the user update the CLI.

If "update fatigue" is a concern, one could limit the notifications to certain intervals (e.g. once a day) or when the difference in major/minor/patch versions exceeds a certain threshold.

[sechmann]

Should the nais binary be able to self-update? We could ship a "bootstrapper binary" through brew/scoop/apt etc, that just stays at a constant version - and then let the nais cli binary update itself.

[jhrv]

Should the nais binary be able to self-update? We could ship a "bootstrapper binary" through brew/scoop/apt etc, that just stays at a constant version - and then let the nais cli binary update itself.

There is some value to let this be handled by the different package managers, and not having to deal with the added complexity. That said, I'm not sure how much it would take.

[tronghn]

Yeah, I think a built-in updater would also be a welcome QoL-improvement, if feasible. If not, just a notification of some kind would help in many cases where a fix or feature is available in newer versions.

[sechmann]

For single-binary applications like this self-updating is not that hard, multiple libraries exist:
https://github.com/sanbornm/go-selfupdate
https://github.com/mouuff/go-rocket-update
https://github.com/minio/selfupdate