Bump default Traefik image to 2.10

[igor-alexandrov]

Traefik 2.10 was released on April 24, 2023, since this 2.9 branch didn't get any updates and security fixes.

The 2.10 branch already got 7 patch releases, and even 2.11 was released one day ago.

This PR bumps default Traefik image to 2.10, after a couple of patch releases I plan to update default image to 2.11.

[morgoth]

FYI: linking to the "migration guide" https://doc.traefik.io/traefik/v2.10/migration/v2/#v210 (which probably won't affect kamal)
and release https://github.com/traefik/traefik/releases/tag/v2.10.0

[igor-alexandrov]

Yes, I forget to say, that I already switched several projects to 2.10.

[morgoth]

I updated to the new traefik version via kamal traefik reboot and for a a short time there was a 502 on the web. Maybe we should warn that the traefik update introduces small downtime?

[igor-alexandrov]

@morgoth you got 502 not because an upgrade of the Traefik, but because kamal traefik reboot literally stops the container: https://github.com/basecamp/kamal/blob/main/lib/kamal/cli/traefik.rb#L23.

Maybe it would be good to add an interactive confirmation to the commands that can be potentially dangerous.

@djmb what do you think?

[morgoth]

Yes, I know it is because of stopping it. I agree on the interactive confirmation addition

[igor-alexandrov]

Thanks @morgoth! I will take care of this.

[djmb]

@igor-alexandrov - yes that's a good idea 👍

We should also add a -y option to allow confirmations to be skipped

[igor-alexandrov]

Sure, will do.

[igor-alexandrov]

@djmb done #730