Bump urllib3 from 1.22 to 1.26.5

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.22 to 1.26.5.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](urllib3/urllib3@1.22...1.26.5)

---
updated-dependencies:
- dependency-name: urllib3
  dependency-type: direct:production
...

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

requirements.txt

@@ -14,5 +14,5 @@ python-dateutil==2.7.3
 pytz==2018.3
 requests==2.18.4
 six==1.11.0
-urllib3==1.22
+urllib3==1.26.5
 whitenoise==3.3.1