Bump urllib3 from 1.23 to 1.24.2

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.23 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@1.23...1.24.2)

Author: dependabot[bot]

requirements.txt

@@ -33,7 +33,7 @@ requests==2.19.1
 six==1.11.0
 tabula-py==1.2.0
 tornado==5.1
-urllib3==1.23
+urllib3==1.24.2
 vine==1.1.4
 Werkzeug==0.15.3
 WTForms==2.2.1