Bump urllib3 from 1.24.3 to 1.26.5 in /install

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.24.3 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@1.24.3...1.26.5)

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

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

install/requirements.txt

@@ -30,7 +30,7 @@ requests==2.21.0
 six==1.12.0
 smmap2==2.0.5
 soupsieve==1.9.1
-urllib3==1.24.3
+urllib3==1.26.5
 websockets==7.0
 Werkzeug==0.15.2
 wrapt==1.11.1