Update Rails version in CI matrix

[Bhacaz]

Hi, with all the new releases of Ruby and Rails. I thought it might be interesting update the Rails version in the matrix CI.

I also removed the unsupported version of Ruby and Rails from the CI matrix.

[rabotyaga]

@Bhacaz Thank you very much for your effort!
Could you please also apply this small patch, it will allow specs with activesupport6.1 to pass:

--- a/lib/chewy/type/witchcraft.rb
+++ b/lib/chewy/type/witchcraft.rb
@@ -58,7 +58,7 @@ module Chewy
       private

         def alicorn
-          @alicorn ||= class_eval <<-RUBY, __FILE__, __LINE__ + 1
+          @alicorn ||= singleton_class.class_eval <<-RUBY, __FILE__, __LINE__ + 1
             -> (locals, object0, crutches) do
               #{composed_values(@type.root, 0)}
             end

They are failing, as in 6.0 there was a line

require "active_support/core_ext/kernel/singleton_class"

in lib/active_support/deprecation/instance_delegator.rb, and in 6.1 it is gone.

[Bhacaz]

@rabotyaga I was searching in ActiveSupport without success what change was causing that error. Thank you 😊

[rabotyaga]

Thanks @Bhacaz!