Bump urllib3 from 1.24.1 to 1.24.2

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.24.1 to 1.24.2.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/1.24.2/CHANGES.rst)
- [Commits](urllib3/urllib3@1.24.1...1.24.2)

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

Author: dependabot-support

requirements.txt

@@ -11,5 +11,5 @@ opbeat==3.5.2
 psycopg2-binary==2.7.7
 pytz==2018.9
 requests==2.21.0
-urllib3==1.24.1
+urllib3==1.24.2
 whitenoise==4.1.2