[6.x] Add Ruby 3.0 and Rails 6.1 compatibility

[tagliala]

Includes changes in #191

Rails 6.1 needs the following changes:

• Add owner: nil to define_method_attribute calls
• Pass options to error add method as keyword argument

Ruby 3 needs the following changes:

• Double splat values arguments passed to DateTimeValue

Ref:

• https://api.rubyonrails.org/v6.0.0/classes/ActiveModel/Errors.html#method-i-add
• https://api.rubyonrails.org/v6.1.0/classes/ActiveModel/Errors.html#method-i-add

Fix: #193

[tagliala]

Everything is green, there are interesting failures with ruby-edge

https://travis-ci.org/github/adzap/validates_timeliness/jobs/750986791

Failure/Error:
       def initialize(year:, month:, day: nil, hour: nil, min: nil, sec: nil)
         @year, @month, @day, @hour, @min, @sec = year, month, day, hour, min, sec
       end

     ArgumentError:
       wrong number of arguments (given 1, expected 0; required keywords: year, month)

I cannot reproduce them with Ruby 3.0.0 on my dev machine

Also, Travis does not have Ruby 3.0.0-rc1

[tagliala]

Working also on Ruby 3.0 compatibility

[tagliala]

FWIW, this gem is still compatible with Ruby 2.4

[tagliala]

Not yet, since the Readme needs to be updated, I'm going to integrate #185

[tagliala]

Preview of the new readme: https://github.com/tagliala/validates_timeliness/tree/rails-61#validatestimeliness-

[tomasztrzos]

When are you planning to merge this pull request?

[slomagnieszka]

Do you have a plan to merge it?

[itay-grudev]

@adzap This MR seems to cover all the checks to get merged.

[tagliala]

~Not yet at the moment, it needs some updates~ Updated to fix tests against Rails edge

[pedrofurtado]

@adzap Any news about this issue? Happy to see this merged and released asap 🎉 🍻

[StoneGod]

Hi, what about released?

[adzap]

@tagliala thanks for getting this together. But I will need a few changes. Please remove the Rdoc conversion, which we can look at that later.

Also, this will be for v6 of the gem which will be for Rails v6.x only, so the v5 appraisals and travis config should be removed.

[adzap]

@tagliala excellent work! so many little tweaks and fixes in the README I'd missed because of the markdown conversion.

[pedrofurtado]

@adzap Happy to see this released in official version for us 🍻 🎉

[adzap]

Looking for feedback from those using the alpha release. A number of you were quite eager for it, so in order to get a final release I would like some confirmation of successful usage.

[itay-grudev]

Can we add automatic testing to the repository in addition to the automatic builds? Also I will add a ticket on our project to upgrade it on production.

[adzap]

We already do via Travis.

[itay-grudev]

It's just called build and I thought it's for gem build and publish instead of testing.

[adzap]

What's it called in other repos? Can you give me an example of some others that are perhaps more up to date?