Golang case insentivity

[acouvreur]

According to https://pkg.go.dev/encoding/json#Unmarshal

Unmarshal matches incoming object keys to the keys used by Marshal (either the struct field name or its tag), preferring an exact match but also accepting a case-insensitive match

To have this library as an drop-in replacement, maybe this behavior should be added.

In the meantime, as the code is generated, I simply change the mapping myself.