build(deps): bump mkdocs-section-index from 0.3.4 to 0.3.5 in /docs (#5)

Bumps
[mkdocs-section-index](https://github.com/oprypin/mkdocs-section-index)
from 0.3.4 to 0.3.5.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/oprypin/mkdocs-section-index/releases">mkdocs-section-index's
releases</a>.</em></p>
<blockquote>
<h2>v0.3.5</h2>
<ul>
<li>Compatibility with mkdocs-material 9.0.7+: <a
href="https://github.com/oprypin/mkdocs-section-index/commit/9e3ac74df822a066f6a2130d663bfb8286b399c9">https://github.com/oprypin/mkdocs-section-index/commit/9e3ac74df822a066f6a2130d663bfb8286b399c9</a>,
<a
href="https://github-redirect.dependabot.com/oprypin/mkdocs-section-index/issues/13">#13</a></li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/oprypin/mkdocs-section-index/commit/6f5824407e4f89659939b50d6bdb885f041d99ac"><code>6f58244</code></a>
v0.3.5</li>
<li><a
href="https://github.com/oprypin/mkdocs-section-index/commit/1d95a2f4b5eca080ac6efd464d7fae60f64c4f0e"><code>1d95a2f</code></a>
Silence type check</li>
<li><a
href="https://github.com/oprypin/mkdocs-section-index/commit/9e3ac74df822a066f6a2130d663bfb8286b399c9"><code>9e3ac74</code></a>
Make sure to expose the <code>active</code> private variable</li>
<li><a
href="https://github.com/oprypin/mkdocs-section-index/commit/f9f8c5f1cd78047ed7bad91cfa1bcc04527a44b8"><code>f9f8c5f</code></a>
Chore dependency upgrade</li>
<li><a
href="https://github.com/oprypin/mkdocs-section-index/commit/9779fc2c6fcec2ea1f89ce9864d154158d6e14d0"><code>9779fc2</code></a>
Migrate to Hatch build and mypy type checker</li>
<li><a
href="https://github.com/oprypin/mkdocs-section-index/commit/2decfd5e97e309cf3c43470351f52a81083c44b0"><code>2decfd5</code></a>
Drop Python 3.6</li>
<li><a
href="https://github.com/oprypin/mkdocs-section-index/commit/b7b83e58dd9c37533f4cd13d3fefd259c6cf5e52"><code>b7b83e5</code></a>
CI: Expand test matrix</li>
<li><a
href="https://github.com/oprypin/mkdocs-section-index/commit/090a49064f276f30ede53e8a87c9b7fd0d4c70bf"><code>090a490</code></a>
Type fixes according to mypy</li>
<li><a
href="https://github.com/oprypin/mkdocs-section-index/commit/a4aa8c5a40104008e4801fe70d2beec92df40acc"><code>a4aa8c5</code></a>
Pin docs dependencies</li>
<li>See full diff in <a
href="https://github.com/oprypin/mkdocs-section-index/compare/v0.3.4...v0.3.5">compare
view</a></li>
</ul>
</details>
<br />


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docs/requirements.txt

@@ -6,4 +6,4 @@ mkdocs-gen-files==0.4.0
 mkdocs-glightbox==0.3.1
 mkdocs-literate-nav==0.6.0
 mkdocs-material==9.0.6
-mkdocs-section-index==0.3.4
+mkdocs-section-index==0.3.5