Drop support for ruby 2.4.x

[rishijain]

Fixes #406

Check list:

• [ ✔️ ] Add an entry to the changelog
• Squash all commits into a single one
• [ ✔️ ] Describe your PR, link issues, etc.

[rishijain]

Hey @etagwerker,
instead of auto-running the build, it says this
First-time contributors need a maintainer to approve running workflows

Will you need anything from me to make this happen?

[nunosilva800]

Thanks @rishijain for your first contribution! I've allowed the tests to go through.
There's only a small consideration here, let me know what you think.

[rishijain]

Hey @nunosilva800,
I have tried to make sense of the failures in build https://github.com/whitesmith/rubycritic/actions/runs/2301117538
but no luck so far.

Can you help me understand what broke this?

Also, I saw similar failures in the last release #405. So this suggests that these failures may not be related to any change I did.

What do you think?

[rishijain]

removing the begin from the block since th target ruby version in rubocop.yml is set to 2.5 and from ruby 2.5 onwards begin block is seemed redundant as per rubocop rules.
here is that PR when the change was done in rubocop rubocop/rubocop#5175

[nunosilva800]

@rishijain I'm still unsure on the exactly why builds for ruby 2.5 are failing. Since Ruby 2.5 is also no longer maintained, I think we can also remove it from the build steps. I'll merge this PR in and raise a new issue. Thanks!

[rishijain]

awesome. thanks, @nunosilva800 .
I will be happy to take that up as well since it would be similar changes. I see that even ruby 2.6 is EOL, why don't we remove both 2.5 and 2.6?

ref: https://www.ruby-lang.org/en/downloads/branches/

[nunosilva800]

2.6 is EOL, but if the CI is still happy with it, I'd say keep it in there. We just not bother with fixing things when the underlying infra / dependencies stop working.