fix publishing upon PR merge

[DenysVuika]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x")

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation
• Other... Please describe:

What is the current behaviour? (You can also link to an open issue here)

upon merge, it takes the name of the source branch, not the target one
https://github.com/Alfresco/alfresco-content-app/actions/runs/4392942322/jobs/7693019234

What is the new behaviour?

fix publishing upon PR merge to develop (use target (develop) branch instead of the closed branch name)

Does this PR introduce a breaking change? (check one with "x")

• Yes
• No

If this PR contains a breaking change, please describe the impact and migration path for existing applications: ...

Other information:

[alxgomz]

The workflow logs you linked are not from a PR merge to master. It looks like a simple PR workflow (going back to the wf summary shows: release.yml / on: pull_request
github.base_ref will be empty on PR merge, and my understanding is that $BRANCH_NAME as returned by the alfresco-build-tools action should handle that case just fine.

[alxgomz]

For example in this workflow run for the same release.yml workflow you can see it's triggered from push on master and the branch name is evaluated as expected: https://github.com/Alfresco/alfresco-content-app/actions/runs/4357569097/jobs/7617039710#step:5:4

[DenysVuika]

@alxgomz we need an extra "alpha" publishing, when code goes from a branch to develop, it should skip the tagging but release alphas