adds testing for ruby 3 and rails 6.1

[tansengming]

this also removes testing for Rails 5 and Ruby 2

[tansengming]

it looks like ruby >= 3 will not work with rails < 6

[danielmorrison]

You can use exclude to remove bad combos from the matrix:

Suggested change

	ruby: [2.5.9, 2.6.10, 2.7.7, 3.0.5, 3.1.3]
	gemfile: [Gemfile, gemfiles/rails60.gemfile, gemfiles/rails52.gemfile, gemfiles/rails51.gemfile]
	ruby: [2.5.9, 2.6.10, 2.7.7, 3.0.5, 3.1.3, 3.2.0]
	gemfile: [Gemfile, gemfiles/rails60.gemfile, gemfiles/rails52.gemfile, gemfiles/rails51.gemfile]
	exclude:
	- ruby: 3.1.3
	gemfile: gemfiles/rails60.gemfile
	- ruby 3.2.0
	gemfile: gemfiles/rails60.gemfile

etc.

[tansengming]

thanks for the tip! I'll try it out next time.