Bump urllib3 from 1.22 to 1.24.2 (#3)

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.22 to 1.24.2.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/master/CHANGES.rst)
- [Commits](urllib3/urllib3@1.22...1.24.2)

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

Author: dependabot[bot]

requirements.txt

@@ -74,7 +74,7 @@ SQLAlchemy==1.1.15
 testpath==0.3.1
 tornado==4.5.2
 traitlets==4.3.2
-urllib3==1.22
+urllib3==1.24.2
 wcwidth==0.1.7
 webencodings==0.5.1
 Werkzeug==0.15.3