Improve incompatible version errors on boot

[zachallaun]

This commit makes a few improvements to the errors shown when Lexical boots with incompatible Elixir/Erlang versions:

• Consistent formatting for all errors
• Prevent an exception that would occur if using an incompatible major version (e.g. Elixir 1.12)
• If both Elixir and Erlang are incompatible, show both errors
• Show full range of compatible versions instead of just the range for the current major version

Example before:

Example after:

[scohen]

Have you tried running this under incompatible erlang versions? I don't think it'll even boot.

[zachallaun]

Have you tried running this under incompatible erlang versions? I don't think it'll even boot.

You're right, it doesn't. That check was there previously, however, so I figured there might be some circumstances where it does boot and then fails later.

[scohen]

My main question is if this will even work for erlang version mismatches. I think it'll only work if we were compiled on an older version and are running on a newer version.

[zachallaun]

@scohen Updated this based on your feedback.

My main question is if this will even work for erlang version mismatches. I think it'll only work if we were compiled on an older version and are running on a newer version.

I think you're right -- packaging_errors is very likely useless because Erlang won't boot. packaging_errors was there to replace verify_packaging, which I believe had the exact same problem. Should we just get rid of packaging_errors entirely?

[scohen]

Should we just get rid of packaging_errors entirely?

Yes.