Bump tox from 4.7.0 to 4.8.0 (#224)

Bumps [tox](https://github.com/tox-dev/tox) from 4.7.0 to 4.8.0.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/tox-dev/tox/releases">tox's
releases</a>.</em></p>
<blockquote>
<h2>4.8.0</h2>
<h2>What's Changed</h2>
<ul>
<li>Correct &quot;notset&quot; typo in --hashseed's --help text. by <a
href="https://github.com/lamby"><code>@​lamby</code></a> in <a
href="https://redirect.github.com/tox-dev/tox/pull/3082">tox-dev/tox#3082</a></li>
<li>Bump pypa/gh-action-pypi-publish from 1.8.8 to 1.8.10 by <a
href="https://github.com/dependabot"><code>@​dependabot</code></a> in <a
href="https://redirect.github.com/tox-dev/tox/pull/3085">tox-dev/tox#3085</a></li>
<li>Allow extending lists with --override foo+=bar by <a
href="https://github.com/stefanor"><code>@​stefanor</code></a> in <a
href="https://redirect.github.com/tox-dev/tox/pull/3088">tox-dev/tox#3088</a></li>
</ul>
<h2>New Contributors</h2>
<ul>
<li><a href="https://github.com/lamby"><code>@​lamby</code></a> made
their first contribution in <a
href="https://redirect.github.com/tox-dev/tox/pull/3082">tox-dev/tox#3082</a></li>
<li><a href="https://github.com/stefanor"><code>@​stefanor</code></a>
made their first contribution in <a
href="https://redirect.github.com/tox-dev/tox/pull/3088">tox-dev/tox#3088</a></li>
</ul>
<p><strong>Full Changelog</strong>: <a
href="https://github.com/tox-dev/tox/compare/4.7.0...4.8.0">https://github.com/tox-dev/tox/compare/4.7.0...4.8.0</a></p>
</blockquote>
</details>
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a
href="https://github.com/tox-dev/tox/blob/main/docs/changelog.rst">tox's
changelog</a>.</em></p>
<blockquote>
<h2>v4.8.0 (2023-08-12)</h2>
<p>Features - 4.8.0</p>
<pre><code>- ``--override`` can now take options in the form of
``foo+=bar`` which
  will append ``bar`` to the end of an existing list/dict, rather than
  replacing it. (:issue:`3087`)
</code></pre>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/tox-dev/tox/commit/f516cb5dde536ff07c9327c722563f3779018eba"><code>f516cb5</code></a>
release 4.8.0</li>
<li><a
href="https://github.com/tox-dev/tox/commit/3b56b5c523e442efa40819a00f4e9ed92de35a3b"><code>3b56b5c</code></a>
Allow extending lists with --override foo+=bar (<a
href="https://redirect.github.com/tox-dev/tox/issues/3088">#3088</a>)</li>
<li><a
href="https://github.com/tox-dev/tox/commit/b40dc3febe91b520dc415c0d9b9bb830248e747e"><code>b40dc3f</code></a>
Bump pypa/gh-action-pypi-publish from 1.8.8 to 1.8.10 (<a
href="https://redirect.github.com/tox-dev/tox/issues/3085">#3085</a>)</li>
<li><a
href="https://github.com/tox-dev/tox/commit/d50ac1d7600e2602028499d2f7ef8f67ba8fb0e8"><code>d50ac1d</code></a>
Correct &quot;notset&quot; typo in --hashseed's --help text. (<a
href="https://redirect.github.com/tox-dev/tox/issues/3082">#3082</a>)</li>
<li>See full diff in <a
href="https://github.com/tox-dev/tox/compare/4.7.0...4.8.0">compare
view</a></li>
</ul>
</details>
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