Update pytest requirement from <8 to <9

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@1.0.0b3...8.1.0)

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

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

Author: dependabot[bot]

pyproject.toml

@@ -64,7 +64,7 @@ all = ["nanopyx[developer,test,jupyter,doc, optional]"]
 developer = ["pyx2pxd>=0.1.1", "black>=23.1.0", "flake8>=6.0.0"]
 test = [
     "nox>=2022.11.21",
-    "pytest<8",
+    "pytest<9",
     "pytest-cov>= 4.0.0",
     "pytest-icdiff>=0.6",    # https://github.com/hjwp/pytest-icdiff
     "pytest-clarity>=1.0.1", # https://pypi.org/project/pytest-clarity/