fix(mm): Replace deprecated Marshmallow Field parameters

[stevenpackardblp]

In Marshmallow 3.13.0, the default and missing parameters of the
Field object were deprecated and replaced with dump_default and
load_default respectively. As these are new parameters added in
version 3.13.0, the minimum version requirement is bumped accordingly.

fixes: #328

[stevenpackardblp]

This would be nice to clean up the warning spews!

[camin-mccluskey]

In case anyone is seeing hundreds of errors, is waiting on this fix to be merged (and uses pytest) adding the following to a pytest.ini file will suppress these warnings:

[pytest]
filterwarnings =
    ignore::DeprecationWarning:marshmallow*
    ignore::DeprecationWarning:dataclasses_json*

[andret13pinto]

I would love for this fix to be merged!

[george-zubrienko]

@stevenpackardblp please update your PR and we can merge ;)

[george-zubrienko]

@stevenpackardblp another ping :) if no reply in a week I'll take over this PR and re-create it

[stevenpackardblp]

@stevenpackardblp another ping :) if no reply in a week I'll take over this PR and re-create it

Let me refresh my workspace this week and see if I can get this rebased. Apologies for missing the first ping.

[russwinch]

it would be great if this could be merged 🙏

[rbreslavsky]

Agree, would be great if this could be addressed!

[stevenpackardblp]

@george-zubrienko big apologies for the delay, I just rebased it.

[stevenpackardblp]

rebased again.

[nomantis]

It would be great to get this merged, so the deprecation warnings can finally be addressed 🙏