fix manager generic constraints

config.go

@@ -11,7 +11,7 @@ import (
 )
 
 // Manager is the top-level configuration schema and viper instance.
-type Manager[T struct{}] struct {
+type Manager[T any] struct {
 	// PreLoad is an optional function that is called before loading the
 	// configuration file.
 	PreLoad func(*Manager[T]) error
@@ -37,7 +37,7 @@ type Manager[T struct{}] struct {
 // NewManager creates a new configuration manager for schema T. Fields in T are
 // responsible for including any necessary `mapstructure` and `validate` tags
 // to ensure proper unmarshalling and validation of the configuration schema.
-func NewManager[T struct{}](configName, configType, configPath string) *Manager[T] {
+func NewManager[T any](configName, configType, configPath string) *Manager[T] {
 	m := &Manager[T]{
 		viper: viper.New(),
 	}