Fix for pydocstyle version 2.0.0 (naive)

Just a quick and naive fix for the changes in pydocstyle==2.0.0 that just broke our testing environment :). Depending on how complex you want this package to be we should probably include actual settings for the new ignore_decorators parameter, but I thought it would be nice to get this out soon for anyone else who had the same problem as us.

Fixes issue #19 (closed).