Reduce serde_with version

[banool]

Summary

Currently Bollard relies on serde_with for a couple of uses in the swagger crate. It specifies serde_with 3+ but 2+ actually works just fine, at least if cargo build is anything to go by. Reducing the minimum version would enable people to use Bollard who can't upgrade to a later version of serde_with / its transitive deps, e.g. serde itself.

Test Plan

I've tried running cargo test --all-features --workspace from the root of the repo on main and I see that not all the tests pass, so I'm not quite sure how to fully test that this works as intended.

[banool]

Oh I see that the swagger code there is all auto generated, so just changing it manually is no good. I'll see if I can fix up the generator part of this.

[fussybeaver]

Thanks, yes you'll need to change the files in codegen/swagger/src/main/resources/bollard/... and regenerate the models as described in the README. There should be some instructions for running the tests in the README too - you'll need to pass some environment variables to bypass the local registry https://github.com/fussybeaver/bollard#integration-tests

[fussybeaver]

Closing due to inactivity. Please re-open if you wish to revive this PR...