Bump flake8-debugger in /{{cookiecutter.app_name}}/requirements

Bumps [flake8-debugger](https://github.com/jbkahn/flake8-debugger) from 3.2.0 to 3.2.1.
- [Release notes](https://github.com/jbkahn/flake8-debugger/releases)
- [Commits](https://github.com/jbkahn/flake8-debugger/compare/3.2.0...3.2.1

)

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