No need to restart drone. Either delete the plugins/gitimage from docker cache or add pull: true
Solution described above seem to work for new pull request just fine. I got error while cloning ref, then drone waited for 5 seconds and succeed on second attempt.
But, if you update existing pull request cloning does not fail. It silently takes previous version, while interface shows latest one. Is there any solution/workaround for this?
Here is related topic: Github Claims that Merge Refs are "Undocumented Feature"