I used `towncrier --draft` to see the full changelog, and decided to "nitpick" it so it reads better as a whole.
This handles `header` similar to Python 3.7 does it, and forwards any other keyword arguments to the Pdb constructor. This allows for `__import__("pdb").set_trace(skip=["foo.*"])`. Fixes https://github.com/pytest-dev/pytest/issues/4416.