Deprecate fail-on-error

[wusatosi]

This pr deprecates fail-on-error and replace them with -fail-level=error.

Would be happy to implement -fail-level in another pr, but needs more directions on design and documentation.

[massongit]

Would be happy to implement -fail-level in another pr, but needs more directions on design and documentation.

Is reviewdog/action-rubocop#124 helpful?

[mongolyy]

@wusatosi

Thank you for the wonderful PR.

Would be happy to implement -fail-level in another pr

I want to support for -fail-level flag.
It seemed that progress was not being made, so I created #67.

If you plan to proceed with this PR, please let me know. I will close my PR accordingly.

[wusatosi]

Hey thanks for the review.

Sorry I must have missed the comment.

Just note that I did not test run this code because I honestly don't know how to test stuff like this. I am also not good at bash scripts. So maybe extra attention is needed to double check I did everything right.

[mongolyy]

@wusatosi
Thank you for your contribution!

I'm sorry.
I responded to it in #67, because we want to support for -fail-level flag too.

I think this pull request is no longer necessary.

[wusatosi]

PR is surpassed by #67 .