Update sphinx-autobuild requirement from ==2021.* to ==2024.* in /requirements (#44)

Updates the requirements on
[sphinx-autobuild](https://github.com/sphinx-doc/sphinx-autobuild) to
permit the latest version.
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a
href="https://github.com/sphinx-doc/sphinx-autobuild/blob/main/NEWS.rst">sphinx-autobuild's
changelog</a>.</em></p>
<blockquote>
<h1>Changelog</h1>
<h2>unreleased</h2>
<h2>2024.02.04 - 2024-02-04</h2>
<ul>
<li>Declare support for Python 3.9, 3.10, 3.11, and 3.12</li>
<li>Drop support for Python 3.8 and earlier</li>
<li>Allow passing relative paths to <code>--ignore</code></li>
<li>Support all valid <code>sphinx-build</code> options (except
Make-mode)</li>
<li>Fix path issues on Windows</li>
<li>Differentiate pre-build command failures from Sphinx failures</li>
</ul>
<h2>2021.03.14 - 2021-03-14</h2>
<ul>
<li>Change output handling for subprocesses.</li>
<li>Present helpful error message when the subprocesses fail.</li>
<li>Skip the main sphinx build, if pre-build commands fail.</li>
</ul>
<h2>2020.09.01 - 2020-09-01</h2>
<ul>
<li>Adopt Calendar Versioning.</li>
<li>Modernize codebase and require Python 3.6+.</li>
<li>Directly depend on <code>sphinx</code>.</li>
<li>Rewritten documentation.</li>
<li>Invoke sphinx via <code>{sys.executable} -m sphinx</code> instead of
<code>sphinx-build</code>.</li>
<li>Trim dependencies down to only <code>livereload</code> and
<code>sphinx</code>.</li>
<li>Drop custom adapter for <code>watchdog</code>.</li>
<li>Drop <code>--poll</code> flag.</li>
<li>Drop single letter variants for flags that were specific to
sphinx-autobuild.</li>
</ul>
<h2>0.7.1 - 2017/07/05</h2>
<ul>
<li>Remove spurious virtualenv directory from published packages.</li>
</ul>
<h2>0.7.0 - 2017/07/05</h2>
<ul>
<li>Add support for python 3.5, 3.6 and deprecate official python 2.6
support.</li>
<li>Add <code>__main__</code> module for python 3.</li>
<li>Add a <code>--version</code> argument.</li>
</ul>
<!-- raw HTML omitted -->
</blockquote>
<p>... (truncated)</p>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/sphinx-doc/sphinx-autobuild/commit/7a8fa1206c65bbd993af7345cf7e9d0f8013d8ed"><code>7a8fa12</code></a>
Release 2024.02.04</li>
<li><a
href="https://github.com/sphinx-doc/sphinx-autobuild/commit/65d4e06a50549f97fd83339d64520385e61defae"><code>65d4e06</code></a>
Update NEWS</li>
<li><a
href="https://github.com/sphinx-doc/sphinx-autobuild/commit/4d7f93926df1fd058aabc01d423942eb60f254a8"><code>4d7f939</code></a>
Add create-release workflow</li>
<li><a
href="https://github.com/sphinx-doc/sphinx-autobuild/commit/76831852bc4c7f44ea36811294bb08850fd705ab"><code>7683185</code></a>
Apply formatting</li>
<li><a
href="https://github.com/sphinx-doc/sphinx-autobuild/commit/d57f1173a8a5d95565448106b5fba8ce8967d91c"><code>d57f117</code></a>
Call Sphinx's build directly</li>
<li><a
href="https://github.com/sphinx-doc/sphinx-autobuild/commit/6f9627e97077efa18db31bf41eacb16bca16a77d"><code>6f9627e</code></a>
Move <code>main()</code> to the top</li>
<li><a
href="https://github.com/sphinx-doc/sphinx-autobuild/commit/19541fb180028efd97ba0696b005623cb3e67aca"><code>19541fb</code></a>
Use Sphinx's argument parser</li>
<li><a
href="https://github.com/sphinx-doc/sphinx-autobuild/commit/88a109889385adb3c0d7f638d8083bcba8e9171c"><code>88a1098</code></a>
Rename <code>portn</code> to <code>port_num</code></li>
<li><a
href="https://github.com/sphinx-doc/sphinx-autobuild/commit/e7c7daa2fb3d16bc6613f3168e0e5bfa3638fbbe"><code>e7c7daa</code></a>
Split <code>pre_build_commands</code> from
<code>_get_build_args()</code></li>
<li><a
href="https://github.com/sphinx-doc/sphinx-autobuild/commit/f62d3257c65e7cdf200bb64eab9f9d52d4f2433a"><code>f62d325</code></a>
Move _get_ignore_handler</li>
<li>Additional commits viewable in <a
href="https://github.com/sphinx-doc/sphinx-autobuild/compare/2021.03.14...2024.02.04">compare
view</a></li>
</ul>
</details>
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</details>

Author: Guts

requirements/documentation.txt

@@ -2,6 +2,6 @@
 # -----------------------
 
 myst-parser[linkify]>=1,<2.1
-sphinx-autobuild==2021.*
+sphinx-autobuild==2024.*
 sphinx-copybutton>=0.2,<1
 sphinx-rtd-theme>=1,<3