Support constants for versions in `fluvio` proc macro

[galibey]

Currently, min_version and max_version attributes of fluvio proc macro support only int literals. We need to add support for constants, e.g.:

const PRODUCER_TRANSFORMATION_API: i16 = 8;
...
#[fluvio(min_version = PRODUCER_TRANSFORMATION_API)]
pub smartmodules: Vec<SmartModuleInvocation>,

and for const fn:

const fn min_transformation_api() -> i16 {
    8
}
...
#[fluvio(min_version = "min_transformation_api")]
pub smartmodules: Vec<SmartModuleInvocation>,

It would also be nice to support any function, not only const but, if it requires a lot of work, it can be done afterward.

[vrrashkov]

I would like to work on this, when the PR gets merged if possible.

Also I noticed that in fluvio-spu-schema/server/smartmodule.rs it's also using constants, but even if it was not, there is no implementation for the enum attributes for min_version,max_version etc. there is only for tag you can see it here. Just wanted to mention it so this can be changed as well.

[galibey]

@vrrashkov yes, sure, go ahead.

The PR is ready to merge, let's wait for release(planned for today) and then do the rebase, and hopefully, all checks will be green.

[github-actions[bot]]

Stale issue message

[github-actions[bot]]

Stale issue message

[ajhunyady]

@galibey, this issue says it's ready to merge after the release (back in November). I assume it should be merged?

[galibey]

@galibey, this issue says it's ready to merge after the release (back in November). I assume it should be merged?

That was regarding another PR. The PR that corresponds to this issue is https://github.com/infinyon/fluvio/pull/3725. Closed as stale.