Update dependency marshmallow to v3.20.2

This MR contains the following updates:

Package	Update	Change
marshmallow (changelog)	minor	==3.17.0 -> ==3.20.2

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Release Notes

marshmallow-code/marshmallow (marshmallow)

v3.20.2

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v3.20.1

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v3.20.0

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v3.19.0

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v3.18.0

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v3.17.1

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Configuration

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