requirements: update sphinxcontrib-serializinghtml requirement

Updates the requirements on [sphinxcontrib-serializinghtml](https://github.com/sphinx-doc/sphinxcontrib-serializinghtml) to permit the latest version.
- [Release notes](https://github.com/sphinx-doc/sphinxcontrib-serializinghtml/releases)
- [Changelog](https://github.com/sphinx-doc/sphinxcontrib-serializinghtml/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinxcontrib-serializinghtml@1.0.0...2.0.0)

---
updated-dependencies:
- dependency-name: sphinxcontrib-serializinghtml
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

broken_trans_deps.txt

@@ -43,5 +43,5 @@ beartype != 0.17.1; python_version == '3.9'
 sphinxcontrib-applehelp <1.0.8
 sphinxcontrib-devhelp <1.0.6
 sphinxcontrib-htmlhelp <2.0.5
-sphinxcontrib-serializinghtml <1.1.10
+sphinxcontrib-serializinghtml <2.0.1
 sphinxcontrib-qthelp <1.0.7