Standardize the elements of lists and tuples

[acr31]

The standardize_custom_type function currently translates the elements of dicts and enums but not lists (or tuples). This means that if you try to serialise a class containing a list of custom classes then they don't get mapped. Also, if you try to serialise a class containing a tuple field it fails to be mapped to a list.

This change adds a mapping covering these cases.

[marcosschroh]

Thanks @acr31

Could you write a test case for this? :-)

[marcosschroh]

closed by https://github.com/marcosschroh/dataclasses-avroschema/pull/211