Require valid module path in getLogger()

[adamchainz]

Description

Sometimes explicit calls to getLogger() don't use a dotted module path, but some other characters that aren't valid in module names like hyphens:

import logging
logger = logging.getLogger("acme-api")

Although the getLogger() docs say:

Choice of these names is entirely up to the developer who is using logging.

Typically apps aim for dotted module paths, per the __name__ pattern. Deviations from this can cause issues, such as not propagating through the intended chain of loggers, such as through an acme root in the example.

Let's detect strings passed to getLogger that aren't valid module paths.