Bump urllib3 from 1.26.3 to 1.26.4 in /requirements

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.26.3 to 1.26.4.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](https://github.com/urllib3/urllib3/compare/1.26.3...1.26.4)

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