Bump urllib3 from 1.24.2 to 1.24.3

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.24.2 to 1.24.3.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/master/CHANGES.rst)
- [Commits](urllib3/urllib3@1.24.2...1.24.3)

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

Author: dependabot-preview[bot]

requirements.txt

@@ -22,7 +22,7 @@ pytz==2018.9              # via -r requirements.in
 pyyaml==5.2               # via -r requirements.in
 requests==2.21.0          # via -r requirements.in
 six==1.10.0               # via cryptography, protobuf, pyopenssl
-urllib3==1.24.2           # via -r requirements.in, requests
+urllib3==1.24.3           # via -r requirements.in, requests
 wheel==0.24.0             # via -r requirements.in
 wrapt==1.11.2             # via deprecated