Bump pytest from 5.2.4 to 8.2.1 in /requirements

Bumps [pytest](https://github.com/pytest-dev/pytest) from 5.2.4 to 8.2.1.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/main/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@5.2.4...8.2.1)

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

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

requirements/tests.txt

@@ -1,6 +1,6 @@
 coveralls==1.8.2
 flake8==3.7.9
-pytest==5.2.4
+pytest==8.2.1
 pytest-cov==2.8.1
 cov-core==1.15.0
 sphinx==2.2.1