chore(deps): update dependency marshmallow to v3.26.2

This MR contains the following updates:

Package	Update	Change
marshmallow (changelog)	minor	==3.21.1 -> ==3.26.2

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Release Notes

marshmallow-code/marshmallow (marshmallow)

v3.26.2

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Bug fixes:

• :cve:2025-68480: Merge error store messages without rebuilding collections. Thanks 카푸치노 for reporting and :user:deckar01 for the fix.

v3.26.1

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v3.26.0

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v3.25.1

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v3.25.0

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v3.24.2

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v3.24.1

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v3.24.0

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v3.23.3

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v3.23.2

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v3.23.1

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v3.23.0

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v3.22.0

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v3.21.3

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v3.21.2

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