(#618) Automatically remove previews from gh-pages

[oeninghe-dataport]

Summary

Removal of previews from GH-pages fails too often.

Instructions for local reproduction and review

• Merge PR
• See the still existing preview

For obvious reasons, this PR is untested.

Relevant tickets, issues, et cetera

Hopefully reduces #618

[dopenguin]

If I am not mistaken, the pipeline would simply stop the next step if the event is closed, right?
But how does this help with the removal of gh-pages deployments?

[oeninghe-dataport]

If I am not mistaken, the pipeline would simply stop the next step if the event is closed, right? But how does this help with the removal of gh-pages deployments?

The pipeline skips building the project when the event is a closed (i.e., merged or declined) pull request.
This is also recommended by https://github.com/rossjrw/pr-preview-action#usage
It speeds up the pipeline runtime at merging - and, even more important - it does not fail when a PR is closed that fails, for example, at npm ci.

The concurrency should prohibit conflicting jobs of the same PR that run concurrently.
This is also recommended by https://github.com/rossjrw/pr-preview-action#set-a-concurrency-group

[dopenguin]

🚀 @oeninghe-dataport