ci: separate Ruby patch and minor releases into separate MRs

Since even minor version Ruby upgrades can be complex, we break ruby version upgrades down into separate patch and minor version upgrades. This allows us to upgrade patch versions while putting off minor version updates.

This means alongside minor upgrade MRs such as eg: gitlab-com/runbooks!4701 (closed) and gitlab-com/runbooks!4700 (closed), we will also get patch version updates.

cc @pguinoiseau