Addresses problem with URL encodings

[GambolingPangolin]

This changes the way URL encoding for query parameters is handled in servant-client, making it possible to correctly encode arbitrary binary data into query parameter values. There is no comparable change for servant-client. Indeed, the query parameter decoding function in the FromHttpApiData typeclass expects to recieve data in Text form for decoding, whereas arbitrary URL-decoded data can only be correctly be represented as a ByteString.

Closes #1418

[alpmestan]

@GambolingPangolin Hello, sorry for the delay, I haven't had much time this summer to carefully follow up on servant stuffs. Would you mind rebasing so that we can see if this passes CI?

There's a bit of unnecessary churn in your patch (imports etc), but it otherwise looks good to me! Thanks for the new test.

[GambolingPangolin]

@alpmestan I shrank the patch and rebased. It would be a nice quality of life improvement to impose formatting rules on the sources so that I could defer code layout more to an automated tool. I totally get the objection to churn, but want to share my 2c.

[alpmestan]

@GambolingPangolin I understand the motivation, having had these discussions countless times, but it's going to be tough to agree on a particular style with all the folks involved in the project =) CI should be running, let's see how this goes.

[akhesaCaro]

To support older version of GHC you need to explicitly import the <> operator.

import Data.Semigroup (<>)

You can also test it using the nix-shell (nix/nix-shell) and provide the version of GHC you want to use. See https://github.com/haskell-servant/servant/tree/master/nix

[GambolingPangolin]

@akhesaCaro Thanks for the tip about testing with nix. I'm confused about the CI failure, though. It looks like the error message concerns a module that I did not touch with my change. Should I change the imports there, or is this a sign of some other problem?

[GambolingPangolin]

@alpmestan @akhesaCaro did you see my previous comment?

[akhesaCaro]

I stopped the support of GHC < 8.6.5 since yesterday. You just have to rebase and it will pass.

[GambolingPangolin]

@akhesaCaro I rebased this patch and it's ready for another try 😁

[GambolingPangolin]

@akhesaCaro bump. Lemme know if you want me to do anything else.