Raise minimum Ruby version to 2.7

[archanaserver]

This contain changes of ruby version support, for >= 2.7', '< 4

[archanaserver]

@ekohl just raised this pr to update ruby version, this was way outdated #75

[ekohl]

The summary of this commit should be Raise minimum Ruby version to 2.7. Typically those kinds of changes are major version bumps.

[archanaserver]

@ekohl ah i marked it as wip and so pushed random change to check the gha workflow result for the rubocop, because rake don't have rule to check rubocop result. do you want me to work on that first?

[ekohl]

If it's WIP then using a draft PR makes it clear to reviewers.

[ekohl]

because rake don't have rule to check rubocop result. do you want me to work on that first?

You can also override the command provided to https://github.com/theforeman/actions/blob/v0/.github/workflows/rubocop.yml. We can also change the action. I recall @evgeni mentioning something similar because you can't enable parallel testing from Rakefile.

The reason I preferred the Rakefile approach in the action was that we very often had old versions of RuboCop that either didn't have the command line utility at all (that came later) or was too old to support --parallel.

By now I think we can start to enforce use of recent enough versions of RuboCop instead of keeping compatibility.

[archanaserver]

This needs rebase once, #75 gets merged!

[ekohl]

#75 includes this and passed, so merging.

[archanaserver]

#75 includes this and passed, so merging.

Thank you @ekohl