Update tox requirement from >=4.31.0 to >=4.55.0

Updates the requirements on [tox](https://github.com/tox-dev/tox) to permit the latest version.
- [Release notes](https://github.com/tox-dev/tox/releases)
- [Changelog](https://github.com/tox-dev/tox/blob/main/docs/changelog.rst)
- [Commits](tox-dev/tox@4.31.0...4.55.0)

---
updated-dependencies:
- dependency-name: tox
  dependency-version: 4.55.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements.txt

@@ -1,5 +1,5 @@
 flit>=3.12.0
-tox>=4.31.0
+tox>=4.55.0
 pytest>=8.0.0
 mdformat >=0.7.0
 mdit_py_plugins >=0.4.0