Bump urllib3 from 1.22 to 1.24.2

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] <[email protected]>

Author: dependabot[bot]

requirements.txt

@@ -21,7 +21,7 @@ pycodestyle==2.3.1
 pyflakes==1.5.0
 requests==2.18.4
 shutilwhich==1.1.0
-urllib3==1.22
+urllib3==1.24.2
 virtualenv==15.1.0
 virtualenv-clone==0.2.6
 Werkzeug==0.14.1