* Update juniper_codegen for syn 1.0.60
syn 1.0.60 has updated it's `Type::__Nonexhaustive` to
`Type::TestExhaustive`, breaking juniper. This updates juniper to use
the recommended idiom for doing exhaustive matching on `Type`, which
fixes this.
Not entirely clear if we need exhaustive matching here or if we could
just use a fallback, but this fixes the build at least.
Also updated the minimum syn so users have to pull it in
* Update example to use relative deps
As otherwise CI fails on this branch
