When used as plugin poetry commands does not return proper exit code

[monim67]

When poethepoet is used as plugin poetry console commands stop returning proper exit codes. For example if poetry lock is not consistent with pyproject poetry lock --check should return exit code 1, instead it returns 0 when poethepoet is installed as plugin.

I think this issue is not same as #71, because my poethepoet tasks return proper exit codes anyway.