Use standard module importlib.metadata instead

pybamm/parameters/parameter_sets.py

@@ -1,5 +1,5 @@
 import warnings
-import importlib_metadata
+import importlib.metadata
 import textwrap
 from collections.abc import Mapping
 
@@ -36,7 +36,7 @@ class ParameterSets(Mapping):
     def __init__(self):
         # Dict of entry points for parameter sets, lazily load entry points as
         self.__all_parameter_sets = dict()
-        for entry_point in importlib_metadata.entry_points(
+        for entry_point in importlib.metadata.entry_points(
             group="pybamm_parameter_sets"
         ):
             self.__all_parameter_sets[entry_point.name] = entry_point