v4

Summary

Breaking changes:

• Pull requests that have the pullpreview label must now be mergeable with the base branch, otherwise the action will not run. This allows to react to the synchronize GitHub Action event, and reduce the amount of runs that end up being skipped (and using your GA minutes).

Other:

• Fixes many bugs, and improves support for long-running jobs.
• Adds PULLPREVIEW_FIRST_RUN to know whether the deployment was just created.