Notification of newer CLI version available

[armcknight]

I recently helped troubleshoot an issue with someone, where the fix was simply updating the CLI tool on their machine, which was roughly 2.5 years old.

This made me think there must be a way we can add a terminal output to notify users that they are using an out-of-date version of the CLI.

[szokeasaurusrex]

This might actually be a bug. The update nagger, I believe, should already do what you want – if it is not notifying about outdated releases, then that seems wrong.

@loewenheim do you have any thoughts here? The update nagger was introduced before I started working on Sentry CLI, do you perhaps have any context on whether it is supposed to notify users in the case of an outdated installation?

[loewenheim]

I don't really have any more context, but surely if the update nagger has any purpose this is it?