Add readme text and installation message to discourage use of this gem

[keithrbennett]

@piotrmurach Thank you for investing your valuable time in your open source projects.

I'd like to address a critical problem with tty.

You said in piotrmurach/tty-command#63 (review):

"As for the tty gem, it is broken in many ways. It is also not the way I wish to encourage building command-line applications."

Use of this gem with Ruby 3.x has been broken since at least August 2021 when I posted the issue at #79 .

You have (understandably) stated on various occasions that your time to work on this gem is limited. The most recent commit was in April 2021, so I guess it is reasonable to expect that the three years will be added on to significantly before this is fixed, if it is ever fixed at all.

I and several others have collectively invested a lot of time in troubleshooting this issue and sharing our suggestions and experiences. It is safe to assume that for each of us who have taken the time to do this, many others experienced the same problem as well.

Therefore, I would like to suggest that you indicate prominently (bold, italic, in a box, etc.), at the top of the readme, that as you say in the PR, you do not recommend using it (or it is retired, etc.). In addition, I recommend a gem post-installation message indicating this as well. This would save users valuable time and set clear expectations about the gem's future.