Update tox requirement from <4.15,>=4.0 to >=4.0,<4.16 (#335)

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@4.0.0...4.15.0)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Zane Selvans <zane.selvans@catalyst.coop>

pyproject.toml

@@ -34,7 +34,7 @@ classifiers = [
 dev = [
     "ruff>=0.3,<0.5",
     "build>=1.0,<1.3",
-    "tox>=4.0,<4.15",  # Python test environment manager
+    "tox>=4.0,<4.16",  # Python test environment manager
     "twine>=3.3,<5.1",  # Used to make releases to PyPI
     "types-requests",
 ]