Bump marshmallow from 3.23.1 to 3.26.1

Bumps [marshmallow](https://github.com/marshmallow-code/marshmallow) from 3.23.1 to 3.26.1.
- [Changelog](https://github.com/marshmallow-code/marshmallow/blob/dev/CHANGELOG.rst)
- [Commits](marshmallow-code/marshmallow@3.23.1...3.26.1)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

src/backend/requirements.txt

@@ -97,7 +97,7 @@ isodate==0.7.2
     # via msrest
 jiter==0.8.0
     # via openai
-marshmallow==3.23.1
+marshmallow==3.26.1
     # via environs
 msal==1.31.1
     # via