Bump irb from 1.2.0 to 1.2.1
Bump irb from 1.2.0 to 1.2.1

Bumps [irb](https://github.com/ruby/irb) from 1.2.0 to 1.2.1.
- [Release notes](https://github.com/ruby/irb/releases)
- [Commits](https://github.com/ruby/irb/commits)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
alphagov/rummager,alphagov/rummager