[feat: add support to metadata on transaction operations](https://github.com/processout/processout-python/commit/01774bb31a251c5c24139f5c06aaa5381c192b75)
6.22.0
6.21.0
Shows whether the balance for a token can be retrieved via the balances endpoint.
6.20.0
Allow developers to retrieve Balances attributed to a customer token.