build(deps): bump urllib3 from 1.25.8 to 1.25.9

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.25.8 to 1.25.9.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/master/CHANGES.rst)
- [Commits](urllib3/urllib3@1.25.8...1.25.9)

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

requirements-pinned.txt

@@ -14,4 +14,4 @@ requests==2.23.0
 securesystemslib[colors,crypto,pynacl]==0.14.2
 six==1.14.0
 subprocess32==3.5.4       ; python_version < '3' # via securesystemslib
-urllib3==1.25.8           # via requests
+urllib3==1.25.9           # via requests