pip(deps-dev): bump pytest-asyncio from 0.25.2 to 0.26.0 in /backend (#90)

Bumps [pytest-asyncio](https://github.com/pytest-dev/pytest-asyncio) from 0.25.2 to 0.26.0.
- [Release notes](https://github.com/pytest-dev/pytest-asyncio/releases)
- [Commits](pytest-dev/pytest-asyncio@v0.25.2...v0.26.0)

---
updated-dependencies:
- dependency-name: pytest-asyncio
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

backend/requirements-dev.txt

@@ -1,7 +1,7 @@
 # Testing
 pytest==8.3.5
 pytest-cov==6.0.0
-pytest-asyncio==0.25.2
+pytest-asyncio==0.26.0
 httpx==0.28.1
 
 # Formatting