chore(deps-dev): update pytest requirement in /store/backend

Updates the requirements on [pytest](https://github.com/pytest-dev/pytest) to permit the latest version.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/main/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@8.4.0...9.0.0)

---
updated-dependencies:
- dependency-name: pytest
  dependency-version: 9.0.0
  dependency-type: direct:development
...

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

Author: dependabot[bot]

store/backend/pyproject.toml

@@ -53,7 +53,7 @@ dev = [
     "flake8~=7.3",
     "pip-chill~=1.0",
     "wheel~=0.36",
-    "pytest~=8.4",
+    "pytest~=9.0",
     "vcrpy~=7.0",
     "pytest-recording~=0.13.1",
 ]