Bump urllib3 from 1.22 to 1.26.5 in /docker

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] <[email protected]>

docker/requirements.txt

@@ -117,7 +117,7 @@ terminado==0.8.1
 testpath==0.3.1
 tornado==5.0.1
 traitlets==4.3.2
-urllib3==1.22
+urllib3==1.26.5
 wcwidth==0.1.7
 webencodings==0.5.1
 Werkzeug==0.14.1