Bump marshmallow from 3.5.1 to 3.8.0 in /auctioning_platform (#128)

Bumps [marshmallow](https://github.com/marshmallow-code/marshmallow) from 3.5.1 to 3.8.0.
- [Release notes](https://github.com/marshmallow-code/marshmallow/releases)
- [Changelog](https://github.com/marshmallow-code/marshmallow/blob/dev/CHANGELOG.rst)
- [Commits](marshmallow-code/marshmallow@3.5.1...3.8.0)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

auctioning_platform/requirements.txt

@@ -31,7 +31,7 @@ injector==0.18.4          # via -r ./auctions/requirements.txt, -r ./auctions_in
 itsdangerous==1.1.0       # via flask, flask-security, flask-wtf
 jinja2==2.11.2            # via flask, flask-babelex
 markupsafe==1.1.1         # via jinja2, wtforms
-marshmallow==3.5.1        # via -r ./web_app/requirements.txt
+marshmallow==3.8.0        # via -r ./web_app/requirements.txt
 packaging==20.4           # via pytest
 passlib==1.7.4            # via flask-security
 pluggy==0.13.1            # via pytest

auctioning_platform/web_app/requirements.txt

@@ -3,6 +3,6 @@ Flask-Security==3.0.0
 Flask-Injector==0.12.0
 Flask==1.1.2
 bcrypt==3.1.7
-marshmallow==3.5.1
+marshmallow==3.8.0
 Flask-Login==0.5.0
 SQLAlchemy==1.3.19