Add comment about pysteps plugin tests: using default name.

Author: ladc

tox.ini

@@ -65,6 +65,7 @@ commands =
     # Test the pysteps plugin support
     pip install cookiecutter
     cookiecutter -f --no-input https://github.com/pySTEPS/cookiecutter-pysteps-plugin -o {temp_dir}/
+    # NB: this should match the default name for a cookiecutter-generated plugin!
     pip install {temp_dir}/pysteps-importer-institution-name
     python {toxinidir}/ci/test_plugin_support.py
     # Check the compiled modules
@@ -126,4 +127,4 @@ commands =
 
 [testenv:black]
 deps = black
-commands = black --check pysteps
+commands = black --check pysteps