Support symbol action types

[davidmason]

Symbol action types cause an error as they are not implicitly converted
to strings when trying to concatenate them with another string.
This just wraps the action type in String(...) when it is being printed so
it should work regardless of the typeof the action type constant.

[imevro]

Use actionTransformer ✊

import createLogger from 'redux-logger';

const logger = createLogger({
  actionTransformer: (action) => ({
    ...action,
    type: String(action.type),
  });
});

[davidmason]

Awesome! I should have read more docs!