[elm-client] Update http operations for elm/http 2.0.0

Created by: andys8

elm/http@2.0.0 was released with a new api. There is a blog post talking about the new api: https://elm-lang.org/blog/working-with-files

The client has to be adapted for the new request type:

Current

https://github.com/OpenAPITools/openapi-generator/blob/b24b6df448878cd8eccae234644e5123785295b5/modules/openapi-generator/src/main/resources/elm/api.mustache#L1-L33

Api

request :
    { method : String
    , headers : List Header
    , url : String
    , body : Body
    , expect : Expect msg
    , timeout : Maybe Float
    , tracker : Maybe String
    }
    -> Cmd msg

https://package.elm-lang.org/packages/elm/http/2.0.0/Http#request

There is also expectWhatEver, which could be useful instead of Http.expectStringResponse (\_ -> Ok ())