docs: mention poetry plugin

Author: johanneskoester

README.md

@@ -2,7 +2,8 @@
 
 This package provides a stable interface for interactions between Snakemake and its executor plugins (WIP).
 
-Plugins should implement the following skeleton to comply with this interface:
+Plugins should implement the following skeleton to comply with this interface.
+It is recommended to use Snakemake's poetry plugin to set up this skeleton (and automated testing) within a python package, see https://github.com/snakemake/poetry-snakemake-plugin.
 
 ```python
 from dataclasses import dataclass, field