[target allocator] Replace deprecated gorilla/mux dependency

[matej-g]

The allocator server uses the router from gorilla/mux, however the project has been deprecated recently (https://github.com/gorilla#gorilla-toolkit) and is no longer actively maintained. We should replace it with an alternative that's still maintained.

[matej-g]

(also if there's agreement on this, happy to take this / propose and replace with an alternative 🙃)

[pavolloffay]

cc) @jaronoff97

@matej-g thanks for reporting this. Do you have any good alternatives in mind?

[matej-g]

Not sure what else is commonly used within Go projects these days, in other projects I'm involved in we use https://github.com/go-chi/chi and we had good experience with it.

[frzifus]

seems that only effects the otel-allocator.

[jaronoff97]

@matej-g the other framework I was considering was gin is there a reason to use chi over gin? I don't have a preference FWIW, just want to add another option in to the mix.

[frzifus]

Is there any specific need to such a framework? As far as I can see, the only functionality that is not in the std lib is the query of the url path variable {job_id}.

[matej-g]

Hm that's also a good point @frzifus, I think I can try to prepare a PR with either alternative (standard lib or one of the frameworks if we need the extra features) and we could continue from there.

[jaronoff97]

@matej-g that would be great, thank you! My worry with the standard library is that if we need to use features that something like gin or chi provide how hard it would be to switch? If it's low enough and we can make it work with the stdlib, then let's go that route. Either way having a PR to compare would be super helpful. Thank you again @matej-g.

[matej-g]

👋 I prepared PR replacing gorilla/mux with gin (#1383), after all due to the need to handle the variable in the path as @frzifus mentioned, there would be more added complexed if we were to coded that by hand, so I believe using gin is a good alternative. Feedback welcome!

[frzifus]

Awesome, I will have a look soon. :)