Bump urllib3 from 1.25.11 to 1.26.2

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.25.11 to 1.26.2.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/master/CHANGES.rst)
- [Commits](https://github.com/urllib3/urllib3/compare/1.25.11...1.26.2)

sphinx-doc/requirements_sphinx.txt

@@ -62,7 +62,7 @@ sphinxcontrib-qthelp==1.0.3
 sphinxcontrib-serializinghtml==1.1.4
 toml==0.10.2
 typed-ast==1.4.1
-urllib3==1.25.11
+urllib3==1.26.2
 utils==1.0.1
 wcwidth==0.1.8
 zipp==3.4.0