Feature: add "outdated" notification on download and submit

[SleeplessByte]

If a student downloads an exercise or submits an exercise that has a newer version of test suite, add the message that their version is outdated and they could update to the latest version. Preferably via a flag in the CLI.

Slack source in #questions

[Smarticles101]

How does the api currently handle this? I imagine it always downloads the latest version of the problem. @iHiD ?

[SleeplessByte]

@Smarticles101 yep it always downloads the newest unless you've downloaded an older version before. Then when you submit, it always just works and you must press the update button on the site and download again in order to update.

[iHiD]

We could even make it interactive :)

[cmccandless]

Then when you submit, it always just works and you must press the update button on the site and download again in order to update.

I just had a use case where apparently I had downloaded the exercise before, never submitted and deleted the exercise directory (TBH, I have no idea why I cleared the directory, thus removing any local evidence of a previous download 🤷‍♂️). When I redownloaded, the test suite was out-of-date, but the update button does not appear on the site until a submission has been made.

It would be nice if that button were visible without submission.

[iHiD]

@cmccandless Mind opening an issue in exercism/exercism for this please, as I think it's a seperate issue and I don't want it to get lost in this thread.

[cmccandless]

@iHiD Done. See exercism/exercism#4694