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)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements_stub.txt

@@ -39,7 +39,7 @@ tensorboard==1.11.0
 tensorflow==1.11.0
 termcolor==1.1.0
 tinydb==3.12.1
-urllib3==1.23
+urllib3==1.24.2
 Werkzeug==0.15.3
 setuptools==39.1.0
 cachetools==3.0.0