Bump urllib3 from 1.25.7 to 1.25.8

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.25.7 to 1.25.8.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](https://github.com/urllib3/urllib3/compare/1.25.7...1.25.8)

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -81,7 +81,7 @@ testpath==0.4.4
 tornado==6.0.4
 tqdm==4.45.0
 traitlets==4.3.3
-urllib3==1.25.7
+urllib3==1.25.8
 wcwidth==0.1.9
 webencodings==0.5.1
 widgetsnbextension==3.5.1