Add output with the number of deleted package versions

[mering]

Use this output also to improve tests

[Chizkiyahu]

@mering
Is fail in https://github.com/Chizkiyahu/delete-untagged-ghcr-action/actions/runs/6785873604
I fix in 22e65b4
still fails in https://github.com/Chizkiyahu/delete-untagged-ghcr-action/actions/runs/6786034181

[mering]

Sorry, rebase error after I had to make changes in #33 (I only tested it with the original version of it). Should be fixed now.

[mering]

Could you please have another look?

[Chizkiyahu]

Could you please have another look?
is fail
https://github.com/Chizkiyahu/delete-untagged-ghcr-action/actions/runs/6810990584/job/18520406549

[mering]

It seems that it is not possible to use this action to clean up in the beginning as it fails when there are no packages (which is the usual step).

I tested it on my repo and the latest version works there.

[Chizkiyahu]

You can add param ignore pkg not exist
And ignore this error in the code

[mering]

You can add param ignore pkg not exist And ignore this error in the code

Let's do this in a separate PR. The functionality of this PR in itself is valuable as is.

[Chizkiyahu]

@mering
is not a bug in your code
https://github.com/orgs/community/discussions/75302

[Chizkiyahu]

@mering
merged in #36