Disable upgrade warnings by default

[iMacTia]

This seems to be an issue again on the jump from v1 to v2. I'm getting a bunch of these:

WARNING: `Faraday::Connection#basic_auth` is deprecated; it will be removed in version 2.0.
While initializing your connection, use `#request(:basic_auth, ...)` instead.
See https://lostisland.github.io/faraday/middleware/authentication for more usage info.
WARNING: `Faraday::Connection#basic_auth` is deprecated; it will be removed in version 2.0.
[...]

Did you move away from the FARADAY_DEPRECATE idea? To be clear, I don't even directly depend on faraday-- it comes through another dependency.

Originally posted by @kyrofa in https://github.com/lostisland/faraday/issues/1089#issuecomment-1086227010

[hyuraku]

@iMacTia We would like to add Faraday#DeprecatedClass to Faraday ver1.xx like https://github.com/lostisland/faraday/commit/6e746fceefe0d1f75535b40a62d846a6a95bf85f , How about?

[iMacTia]

@hyuraku yep that would work!

[hyuraku]

@iMacTia I could not solve the warning by adding Faraday#DeprecatedClass because the class could not hide custom warning message. I suggest adding the module in lib/faraday/warning.rb below to hide the warning message; how about?

module CustomWarningFilter
  def warn(message)
    deprecate = ENV['FARADAY_DEPRECATE'].to_s.downcase
    if !(deprecate == '1' || deprecate == 'warn')
      super
    end
  end
end
Warning.extend CustomWarningFilter

[iMacTia]

Oh right, Faraday#DeprecatedClass deprecates an entire class, but I thought you wanted to use Faraday::Deprecate#deprecate from that PR. That should allow you do deprecate individual methods with a similar configurable behaviour.

I'd rather not extend or mess with public standard classes like Warning as that could have unexpected repercussions on projects and affects things outside of Faraday's control.

[iMacTia]

This was fixed in #1438 🎉 Thank you @hyuraku 🙏