Bump pytest from 6.2.5 to 7.0.1 in /backend

Bumps [pytest](https://github.com/pytest-dev/pytest) from 6.2.5 to 7.0.1.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/main/CHANGELOG.rst)
- [Commits](https://github.com/pytest-dev/pytest/compare/6.2.5...7.0.1)

---
updated-dependencies:
- dependency-name: pytest
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

backend/requirements.txt

@@ -5,6 +5,6 @@ greenlet==1.1.2
 python-engineio==3.14.2
 python-socketio==4.6.1
 six==1.16.0
-pytest==6.2.5
+pytest==7.0.1
 requests==2.27.1
 discord-webhook==0.14.0