Wait for pdb if it's passed to pytest_args

[remcohaszing]

This prevents multiple pdb sessions from running simultaneously when
running:

    pytest-watch -- --pdb

Previously this could result into annoying behaviour.

[blueyed]

LGTM, I think this bugged my already a few times.

[joeyespo]

Why not run pytest-watch --pdb instead? That was added in to handle this case.

I'm all for reducing frustration and confusion though 👍 And this is well-aligned with #57.

Thanks, @remcohaszing!

[remcohaszing]

Because it takes so many keypresses to properly modify ptw -- --maxfail 1 -vv ;)

[blueyed]

@remcohaszing
You can use -x instead of --maxfail 1 btw (AFAICS).

[remcohaszing]

@blueyed I didn't know, thanks for the tip. 😸