add missing import of sys

Author: mcflugen

babelizer/data/{{cookiecutter.package_name}}/{{cookiecutter.package_name}}/bmi.py

@@ -10,6 +10,7 @@
 from .lib import {{ classes|join(', ') }}
 
 {%- else %}
+import sys
 if sys.version_info >= (3, 12):  # pragma: no cover (PY12+)
     import importlib.resources as importlib_resources
 else:  # pragma: no cover (<PY312)