_yaml.py: Quieten a lint in Python < 3.6

For Python before 3.6, `path.resolve()` could not take the `strict`
keyword argument.  Linting on such Python versions will raise an unnecessary
issue given the check present.  As such, quieten that lint.  Unfortunately
this ends up making the line quite long (though not too long).

Signed-off-by: Daniel Silverstone <daniel.silverstone@codethink.co.uk>