Allow `.getLogger()` with no args

[dhalbert]

CPython allows leaving out the name of the logger, to get the root logger:
https://docs.python.org/3/library/logging.html?highlight=logging#logging.getLogger

logging.getLogger(name=None)

Return a logger with the specified name or, if name is None, return a logger which is the root logger of the hierarchy. If specified, the name is typically a dot-separated hierarchical name like ‘a’, ‘a.b’ or ‘a.b.c.d’. Choice of these names is entirely up to the developer who is using logging.