build(deps): update pytest requirement from <9,>=8.4.2 to >=9.1.1,<10

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@8.4.2...9.1.1)

---
updated-dependencies:
- dependency-name: pytest
  dependency-version: 9.1.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements/testing.txt

@@ -1,5 +1,5 @@
 # pip install -r requirements/testing.txt
-pytest>=8.4.2,<9
+pytest>=9.1.1,<10
 pytest-cov>=7.1.0,<8
 Flask>=3.1.3,<4 
 gevent>=26.5.0,<27