Open Issue on alert

Just like the comment on alert feature, it would be nice if the action could open a new issue on alert and/or with the results. This way, the action does not have to be linked to a PR, for example if we want to have a scheduled benchmarking run on a certain branch.

This would go hand in hand with #154 (Output a Markdown result directly for custom integration), as there could be one common representation of the result that could be used in the comment, job summary, new issue, or direct for custom integration.