Update tox requirement from ==3.25.* to ==4.23.*

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@3.25.0...4.23.2)

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

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

requirements_dev.txt

@@ -26,7 +26,7 @@ pytest==7.2.*
 pytest-cov==3.0.*
 pytest-randomly==3.12.*
 pytest-rerunfailures==10.*
-tox==3.25.*
+tox==4.23.*
 
 # Documentation (for devs)
 # -----------------------