Prefer any over interface{}

[StevenACoffman]

This just replaces interface{} with any. This may help with #3414

Signed-off-by: Steve Coffman steve@khanacademy.org

[StevenACoffman]

@Brookke hey, after I rebased this with your PR, I'm getting this modelgen error. May be unrelated to your change, but if you get a chance to take a look, I would appreciate it.

[StevenACoffman]

@evellior Rather than figure out what was causing the inconsistency (sometimes generate with interface{} and sometimes with any), I tried to just switch everything to any. However, it looks like there's a problem with the modelgen:

Generated github.com/99designs/gqlgen/codegen/testserver/compliant-int/generated-default in 0.61s
Generated github.com/99designs/gqlgen/codegen/testserver/compliant-int/generated-compliant-strict in 0.48s
modelgen: package cannot be nil
exit status 3
codegen/testserver/followschema/generated_test.go:2: running "go": exit status 1
Generated github.com/99designs/gqlgen/codegen/testserver/nullabledirectives/generated in 0.81s
modelgen: package cannot be nil
exit status 3
codegen/testserver/singlefile/generated_test.go:2: running "go": exit status 1

After my day job, I'll try to take a look at it some more, but if anything jumps out at you as the cause, I would appreciate some extra eyes.

[StevenACoffman]

So I am a doofus. :) any is just a type alias for interface{}, so when you are making a conditional based on the type, you still need to look for interface{} rather than any. This was a self-inflicted brain injury on my part.