[BUG] publicV2/data.py: Data.get_metrics_animals is missing a return statement

[ChrisMyers]

Describe the bug
In publicV2/data.py, the method Data.get_metrics_animals() is missing a return statement, and therefore does not return the results of the call to self.api.get(url_suffix, json=params). All the other methods on the Data class appear to correctly return the result of the api call.

Expected behavior
I expect the method to return the result of the api call, but nothing (None) is returned.

[Mopsgeschwindigkeit]

will be resolved with #52