validation: allow Ints passed to Float arguments

[darl]

Maybe translation similar to #1136 would be better.
But I don't know reasons behind #1136 implementation.

[ghostdogpr]

The reason behind the transformation of StringValue into EnumValue is so that when you use Field metadata, you get a value of a type that matches the schema. Basically it's coercing "early" so that you don't even need to do it in the ArgBuilder. I guess we should apply the same logic for this case. @frekw right? What do you think?

[ghostdogpr]

@darl I opened #1150

[frekw]

@ghostdogpr yeah I think doing it like in #1150 is the only way to do it since we're basically paving over limitations in JSON. If I read the spec correctly, coercion should only be applied when we're dealing with variables so doing it like this probably runs the risk of accepting invalid queries for Content-Type: application/graphql.

[ghostdogpr]

@frekw shouldn't it be applied to arguments too? http://spec.graphql.org/June2018/#sec-Coercing-Field-Arguments

[ghostdogpr]

Answering myself: not for enums, but for float yes. Will handle it in my other PR.