Add ruby3 support

[kvokka]

Removed EOL Ruby versions and added actual instead
Keep in mind, that the most recent versions require TLS in SMTP requests, which required to update a couple of requests.
Made specs green again

Added Ruby 3 Ractor support (technically lib/tcr/recordable_tcp_socket.rb#13 was the only thing which i initially needed)

[mgruner]

@kvokka we have issues with this part where tcr.rb overrides Socket.tcp:

class Socket
  class << self
    alias_method :real_tcp, :tcp

    def tcp(host, port, *socket_opts)
      if TCR.configuration.hook_tcp_ports.include?(port)
        TCR::RecordableTCPSocket.new(host, port, TCR.cassette)
      else
        real_tcp(host, port, *socket_opts)
      end
    end
  end
end

In Ruby 3, that needs to be **socket_opts rather than *socket_opts. It yields TypeError: no implicit conversion of Hash into String. Occurs when calling Net::IMAP.new.

Btw, it seems that the owner of this repository @robforman is not active on GitHub anymore since 2018. Maybe tcr needs to be forked?

[robforman]

@mgruner I'm not as active. Want to be a collaborator on the project?

[mgruner]

@robforman thank you for your proposal, I needed a moment to reflect on it.

Can I support you in getting tcr ready for Ruby 3, handling valid incoming PRs, and keeping it alive for future versions, including gem releases? Yes.

If that's fine for you, feel free to add me here and possibly on rubygems.org (username mrtngrnr). Thanks!

[w-A-L-L-e]

**socket_opts still gives errors for me when using ldap bind.
This works (and as I only use this gem in development, I dont mind the connect timeout and resolv timeout to be stripped):

class Socket
  class << self
    alias_method :real_tcp, :tcp

    def tcp(host, port, *socket_opts)
      if TCR.configuration.hook_tcp_ports.include?(port)
        TCR::RecordableTCPSocket.new(host, port, TCR.cassette)
      else
        # PATCHED for ruby 3.1.2, **socket_opts gives less errors, but still breaks on bind
        # for now, just omit the extra 2 options entirely seems to fix most issues for now:
        # real_tcp(host, port, *socket_opts)
        real_tcp(host, port)
      end
    end
  end
end

[sionide21]

Fixed in #41