Update Rubocop and other gems + fix errors

[archiloque]

When working on the project I have some errors because I'm using Ruby 3.0 and the Rubobop version used by the project is not aware of this version so I get an error message (Supported versions: 2.3, 2.4, 2.5, 2.6, 2.7).

I have update Rubocop and took the opportunity to update the other gems at the same time since they don't have any impact.

After running the auto fix, I manually fixed the issues that have a low impact on the code and disable checks in the files for the other ones, the number of changes seems reasonable.

I also enabled the new rules for Rubocop as suggested bu the doc.

I also added the new rubocop-rake gem since it has no impact but I didn't added rubocop-rspec because it detects a lot of violations which should have a big impact on the code.

If you want I can add it and fix the violations, I wanted to know what you prefer before doing the required work, let me know what you prefer.

[ggrossetie]

Looks good, I would rather leave rubocop-rake out for now. I don't think we need it, one less dependency, one less thing to worry about 😄

[archiloque]

Looks good, I would rather leave rubocop-rake out for now. I don't think we need it, one less dependency, one less thing to worry about 😄

I've removed it, I also took the opportunity to bump the required ruby/.ruby-version to make it match the one I added in ruby/.rubocop.yml (I forgot I added it), tell me if you prefer to keep the 2.6 version.

[ggrossetie]

I've removed it, I also took the opportunity to bump the required ruby/.ruby-version to make it match the one I added in ruby/.rubocop.yml (I forgot I added it), tell me if you prefer to keep the 2.6 version.

Perfect, I'm fine with Ruby 2.7.
Ruby 2.6 is already in "security maintenance", so it's probably better to use Ruby 2.7 as the minimum version: https://www.ruby-lang.org/en/downloads/branches/

[ggrossetie]

Thanks 👍🏻