Bump flask-marshmallow from 0.14.0 to 0.15.0

Bumps [flask-marshmallow](https://github.com/marshmallow-code/flask-marshmallow) from 0.14.0 to 0.15.0.
- [Release notes](https://github.com/marshmallow-code/flask-marshmallow/releases)
- [Changelog](https://github.com/marshmallow-code/flask-marshmallow/blob/dev/CHANGELOG.rst)
- [Commits](marshmallow-code/flask-marshmallow@0.14.0...0.15.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -1,5 +1,5 @@
 setuptools >= 21.0.0
 gunicorn==20.1.0
-flask-marshmallow==0.14.0
+flask-marshmallow==0.15.0
 flask-cors==3.0.10
 connexion[swagger-ui]==2.14.2