replace encoding/json with goccy/go-json

[roeest]

goccy/go-json is a more performant version of encoding/json.
Using it seems to improve the amount of memory allocated and ns/op.
I used the benchmark in _examples/starwars to compare the performance:

encoding/json version:

BenchmarkSimpleQueryNoArgs-12              48986             23931 ns/op            8237 B/op        146 allocs/op

goccy/go-json version:

BenchmarkSimpleQueryNoArgs-12              53048             21194 ns/op            7824 B/op        141 allocs/op

On average i observed about a 5% improvement

[coveralls]

Coverage remained the same at 75.653% when pulling df55d5d on roeest:master into 3087cf3 on 99designs:master.

[mtibben]

With just a 5% improvement in reality this might shave off microseconds from a typical request. Personally I don't think it's worth diverging from the stdlib for tiny gains

[auvn]

@roeest may you check the diff if it goes with https://github.com/json-iterator/go ?

[roeest]

@roeest may you check the diff if it goes with https://github.com/json-iterator/go ?

I could do that. I'm also considering expanding the size of the requests and responses and adding another test to the benchmark, I was looking at the doc and the improvement is more significant for larger data. Now I just need to find some time to do it :)