Bumps [@openzeppelin/gsn-helpers](https://github.com/OpenZeppelin/openzeppelin-gsn-helpers) from 0.2.0 to 0.2.1.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-gsn-helpers/releases)
- [Commits](https://github.com/OpenZeppelin/openzeppelin-gsn-helpers/compare/v0.2.0...v0.2.1)

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