Update tox requirement from <4,>=3.23.0 to >=3.23.0,<5

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@3.23.0...4.4.5)

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

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

Author: dependabot[bot]

requirements.txt

@@ -1,3 +1,3 @@
 domdf-python-tools>=2.8.1
 pytest>=6.2.2
-tox<4,>=3.23.0
+tox>=3.23.0,<5