Remove pending merge broken

[grindtildeath]

When removing a pending merge, and pending merge is the only one left in the yml file, the script tries to re aggregate the submodule branch after the yml file was deleted. It should instead reset to the default branch from upstream (according to Odoo version)

Traceback (most recent call last):
  File "/home/xxxxx/.local/bin/otools-pending", line 8, in <module>
    sys.exit(cli())
  File "/home/xxxxx/.local/lib/python3.10/site-packages/click/core.py", line 1161, in __call__
    return self.main(*args, **kwargs)
  File "/home/xxxxx/.local/lib/python3.10/site-packages/click/core.py", line 1082, in main
    rv = self.invoke(ctx)
  File "/home/xxxxx/.local/lib/python3.10/site-packages/click/core.py", line 1697, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/xxxxx/.local/lib/python3.10/site-packages/click/core.py", line 1443, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/xxxxx/.local/lib/python3.10/site-packages/click/core.py", line 788, in invoke
    return __callback(*args, **kwargs)
  File "/home/xxxxx/.local/lib/python3.10/site-packages/odoo_tools/cli/pending.py", line 102, in remove_pending
    pm_utils.remove_pending(entity_url, aggregate=aggregate)
  File "/home/xxxxx/.local/lib/python3.10/site-packages/odoo_tools/utils/pending_merge.py", line 592, in remove_pending
    aggregator = repo.get_aggregator()
  File "/home/xxxxx/.local/lib/python3.10/site-packages/odoo_tools/utils/pending_merge.py", line 386, in get_aggregator
    return RepoAggregator(self, **extra_config)
  File "/home/xxxxx/.local/lib/python3.10/site-packages/odoo_tools/utils/pending_merge.py", line 526, in __init__
    config = git_aggregator.config.load_config(self.pm_repo.abs_merges_path)[0]
  File "/home/xxxxx/.local/lib/python3.10/site-packages/git_aggregator/config.py", line 149, in load_config
    raise ConfigException('Unable to find configuration file: %s' % config)
git_aggregator.exception.ConfigException: Unable to find configuration file: /home/xxxxx/devcode/yyyyy_odoo/pending-merges.d/mail.yml