corrected CustomField.Options field to string from []string

snipcart/common.go

@@ -39,4 +39,7 @@ type Client struct {
 type CustomField struct {
 	Name     string `json:"name"`
 	Value    string `json:"value"`
+	Type     string `json:"type,omitempty"`
+	Options  string `json:"options,omitempty"`
+	Required bool   `json:"required"`
 }