Improve publish-rhel script [DI-343]

[JackPGreen]

The action failed but without providing enough information to understand why.

Changes:

• Log the get_image function response (JSON) in case of failure
• Improve failure annotation reporting (as per Improve GitHub Action failure reporting annotation #821)
• Address all Shellcheck warnings in case related
  • Declare and assign separately to avoid masking return values
  • Prefer putting braces around variable references even when not strictly required
  • Quote the rhs of = in [[ ]] to prevent glob matchingQuote the rhs of = in [[ ]] to prevent glob matching

Partially addresses DI-343

Post-merge actions:

• backport

[ldziedziul]

Have you tested it?

[JackPGreen]

Have you tested it?

I hadn't - because it's destructive I wanted to wait for a review.

As it's already had one approval, I've run it here ✅.

Unless you could think of a better way to test?

[ldziedziul]

Why do we need it?

[JackPGreen]

For the echoerr function.

[ldziedziul]

It's confusing that we have a test code in the production script. I would suggest either inline this function as it's very small or move it to another file echo.functions.sh/log.functions.sh?

[JackPGreen]

It's confusing that we have a test code in the production script.

Good point.

I would suggest either inline this function as it's very small or move it to another file echo.functions.sh/log.functions.sh?

For now I've duplicated it.
Ideally it should be externalised - but as hazelcast-packaging directly references the script without any other context, a larger change is required to support that.