Install importlib_resources on buildkite

.buildkite/pipeline.yml

@@ -15,7 +15,7 @@ steps:
       pip install "pytest<6"
       pip install coverage pytest-pycodestyle
       pip install --upgrade "mantle>=2.0.0"
-      pip install vcdvcd decorator kratos
+      pip install vcdvcd decorator kratos importlib_resources
       pip install DeCiDa scipy numpy
 
       # install fault