Bump sphinx from 4.1.1 to 4.1.2
diff --git a/docs/requirements.txt b/docs/requirements.txt
index ca85e46e8..67cbc0079 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,4 +1,4 @@
 alabaster==0.7.12
-Sphinx==4.1.1
+Sphinx==4.1.2
 sphinx-rtd-theme==0.5.2
 sphinx-copybutton==0.4.0

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 4.1.1 to 4.1.2.
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a href="https://github.com/sphinx-doc/sphinx/blob/4.x/CHANGES">sphinx's changelog</a>.</em></p>
<blockquote>
<h1>Release 4.1.2 (released Jul 27, 2021)</h1>
<h2>Incompatible changes</h2>
<ul>
<li><a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9435">#9435</a>: linkcheck: Disable checking automatically generated anchors on
github.com (ex. anchors in reST/Markdown documents)</li>
</ul>
<h2>Bugs fixed</h2>
<ul>
<li><a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9489">#9489</a>: autodoc: Custom types using <code>typing.NewType</code> are not displayed well
with the HEAD of 3.10</li>
<li><a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9490">#9490</a>: autodoc: Some objects under <code>typing</code> module are not displayed well
with the HEAD of 3.10</li>
<li><a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9436">#9436</a>, <a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9471">#9471</a>: autodoc: crashed if <code>autodoc_class_signature = &quot;separated&quot;</code></li>
<li><a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9456">#9456</a>: html search: html_copy_source can't control the search summaries</li>
<li><a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9435">#9435</a>: linkcheck: Failed to check anchors in github.com</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="https://github.com/sphinx-doc/sphinx/commit/4ba5c21b0182557157710a457bed470d335f7571"><code>4ba5c21</code></a> Bump to 4.1.2 final</li>
<li><a href="https://github.com/sphinx-doc/sphinx/commit/4dc45f0a3d7e1cd7a1df524c23e8883e7639e95a"><code>4dc45f0</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9494">#9494</a> from tk0miya/9456_revert_9129</li>
<li><a href="https://github.com/sphinx-doc/sphinx/commit/df562b4343aaa29163aefafe04906cb5bf7ffe83"><code>df562b4</code></a> Merge branch '4.1.x' into 9456_revert_9129</li>
<li><a href="https://github.com/sphinx-doc/sphinx/commit/5d8f925e02e6ab339deb8a603a7355d46571c3e4"><code>5d8f925</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9493">#9493</a> from tk0miya/9436_autodoc_class_signature</li>
<li><a href="https://github.com/sphinx-doc/sphinx/commit/ef53dec9c59a2379b69416fdd45c163606237c94"><code>ef53dec</code></a> Fix <a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9456">#9456</a>: html search: html_copy_source can't control the search summaries</li>
<li><a href="https://github.com/sphinx-doc/sphinx/commit/4f364a30bc6e3df96cf8e1d7dd1a0d2115c30f0b"><code>4f364a3</code></a> Fix <a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9436">#9436</a>, <a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9471">#9471</a>: autodoc: crashed if autodoc_class_signature = &quot;separated&quot;</li>
<li><a href="https://github.com/sphinx-doc/sphinx/commit/9218ad4adc20297ab3d3591b0513604bf1e35631"><code>9218ad4</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9491">#9491</a> from tk0miya/9489_NewType</li>
<li><a href="https://github.com/sphinx-doc/sphinx/commit/68fb54806f2ce476159e5607fc303342c29e31be"><code>68fb548</code></a> Fix <a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9490">#9490</a>: autodoc: Some typing.* objects are broken</li>
<li><a href="https://github.com/sphinx-doc/sphinx/commit/771507e073d46b12bcbdc56346a4ef06d2f653f5"><code>771507e</code></a> Fix <a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9489">#9489</a>: autodoc: Custom types using typing.NewType are broken</li>
<li><a href="https://github.com/sphinx-doc/sphinx/commit/9ebdc987b08a52e857fee5a4099d64baadfae729"><code>9ebdc98</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/sphinx-doc/sphinx/issues/9467">#9467</a> from tk0miya/9435_disable_rewrite_github_anchor</li>
<li>Additional commits viewable in <a href="https://github.com/sphinx-doc/sphinx/compare/v4.1.1...v4.1.2">compare view</a></li>
</ul>
</details>
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