Delete branches which are going to be merged into non default branch

[alaex777]

Hi! First of all, I would like to thank you for your project, it's great, it helps us every day.

Unfortunately there is a problem. Your script deletes a branch which is going to be merged and it has an open pull request not to the default branch.

It seams like github api method f'{self.github_base_url}/repos/{self.github_repo}/commits/{commit_hash}/pulls' shows only pull requests to the main branch. Maybe you should just take all open pull requests and check for branches there. It seams to solve this issue.

[luispabon]

Thanks for the report, I'll look into this.