I know of Sweep <https://docs.sweep.dev>, but honestly the SOTA on SWE-bench, which is basically exactly what you're asking for, is only about a 25% success rate, so expect very mediocre results.
Another one is https://www.github.com/trafficguard/nous which provides a software dev agent that can find/clone repos, create a branch, search in a repo, then delegates to Aider for the code editing in the edit/compile/lint/test loop, and raise a merge request.