Move issues on PR activity

[koppor]

• When a contributor opens a PR, we needed to manually update the state in the project.
• When we closed a PR without merging, we needed to manually update the state in the project (and also manually unassign the user)

With this PR, we get this in an automated fassion.

Following PRs need to be monitored and these files updated as soon as the PRs are merged:

• Add output "ticketNumber" neofinancial/ticket-check-action#58
• Add "issue-number" as parameter m7kvqbe1/github-action-move-issues#38

Mandatory checks

• I own the copyright of the code submitted and I licence it under the MIT license
• Change in CHANGELOG.md described in a way that is understandable for the average user (if change is visible to the user)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.

[trag-bot]

@trag-bot didn't find any issues in the code! ✅✨

[github-actions]

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