⬆️ Bump marshmallow from 3.21.0 to 3.21.1 (#60)

Bumps [marshmallow](https://github.com/marshmallow-code/marshmallow) from 3.21.0 to 3.21.1.
- [Changelog](https://github.com/marshmallow-code/marshmallow/blob/dev/CHANGELOG.rst)
- [Commits](marshmallow-code/marshmallow@3.21.0...3.21.1)

---
updated-dependencies:
- dependency-name: marshmallow
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>