chore(deps): update dependency tox to v4.26.0 (#809)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [tox](https://redirect.github.com/tox-dev/tox)
([changelog](https://tox.wiki/en/latest/changelog.html)) | `==4.25.0` ->
`==4.26.0` |
[![age](https://developer.mend.io/api/mc/badges/age/pypi/tox/4.26.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![adoption](https://developer.mend.io/api/mc/badges/adoption/pypi/tox/4.26.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![passing](https://developer.mend.io/api/mc/badges/compatibility/pypi/tox/4.25.0/4.26.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/tox/4.25.0/4.26.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|

---

### Release Notes

<details>
<summary>tox-dev/tox (tox)</summary>

###
[`v4.26.0`](https://redirect.github.com/tox-dev/tox/releases/tag/4.26.0)

[Compare
Source](https://redirect.github.com/tox-dev/tox/compare/4.25.0...4.26.0)

<!-- Release notes generated using configuration in .github/release.yml
at 4.26.0 -->

#### What's Changed

- Add a missing quote in a TOML example @&#8203; `config.rst` by
[@&#8203;webknjaz](https://redirect.github.com/webknjaz) in
[https://github.com/tox-dev/tox/pull/3509](https://redirect.github.com/tox-dev/tox/pull/3509)
- Add colour to GitHub Actions CI logs by
[@&#8203;hugovk](https://redirect.github.com/hugovk) in
[https://github.com/tox-dev/tox/pull/3525](https://redirect.github.com/tox-dev/tox/pull/3525)
- Fix using deprecated virtualenv option `--wheel` by
[@&#8203;robsdedude](https://redirect.github.com/robsdedude) in
[https://github.com/tox-dev/tox/pull/3528](https://redirect.github.com/tox-dev/tox/pull/3528)
- Fix custom HelpFormatter for Python 3.14 by
[@&#8203;The-Compiler](https://redirect.github.com/The-Compiler) in
[https://github.com/tox-dev/tox/pull/3524](https://redirect.github.com/tox-dev/tox/pull/3524)
- Drop support for EOL Python 3.8 by
[@&#8203;hugovk](https://redirect.github.com/hugovk) in
[https://github.com/tox-dev/tox/pull/3527](https://redirect.github.com/tox-dev/tox/pull/3527)
- Test with Python 3.14 by
[@&#8203;edgarrmondragon](https://redirect.github.com/edgarrmondragon)
in
[https://github.com/tox-dev/tox/pull/3533](https://redirect.github.com/tox-dev/tox/pull/3533)
- Fix for tox4 regression issue with setenv file and substitutions
([#&#8203;2435](https://redirect.github.com/tox-dev/tox/issues/2435)) by
[@&#8203;realitycheck](https://redirect.github.com/realitycheck) in
[https://github.com/tox-dev/tox/pull/3521](https://redirect.github.com/tox-dev/tox/pull/3521)
- Feat: free-threaded python support by
[@&#8203;robsdedude](https://redirect.github.com/robsdedude) in
[https://github.com/tox-dev/tox/pull/3526](https://redirect.github.com/tox-dev/tox/pull/3526)

#### New Contributors

- [@&#8203;edgarrmondragon](https://redirect.github.com/edgarrmondragon)
made their first contribution in
[https://github.com/tox-dev/tox/pull/3533](https://redirect.github.com/tox-dev/tox/pull/3533)
- [@&#8203;realitycheck](https://redirect.github.com/realitycheck) made
their first contribution in
[https://github.com/tox-dev/tox/pull/3521](https://redirect.github.com/tox-dev/tox/pull/3521)

**Full Changelog**:
tox-dev/tox@4.25.0...4.26.0

</details>

---

### Configuration

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Automerge - At any time (no schedule defined).

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♻ **Rebasing**: Whenever PR is behind base branch, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

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requirements-dev.txt

@@ -1,6 +1,6 @@
 -r requirements.txt
 -r requirements-test.txt
-tox==4.25.0
+tox==4.26.0
 wheel==0.46.1
 Sphinx==7.4.7
 sphinx-rtd-theme==3.0.2