Incorrect use of strconv.Unquote in messages.go

[IvanWillsBI]

func (m *Message) AddVariable(variable string, value interface{}) error {
	if m.variables == nil {
		m.variables = make(map[string]string)
	}

	j, err := json.Marshal(value)
	if err != nil {
		return err
	}

	encoded := string(j)
	v, err := strconv.Unquote(encoded)
	if err != nil {
		v = encoded
	}

	m.variables[variable] = v
	return nil
}

Doesn't work for boolean values or numbers (non string values, as they don't appear as ""foo"")

Therefore, in my mailgun template which uses {{#if }} handlebars, I cannot check the boolean value, as it is sent as a string