coerce_keys option

[lidatong]

The py-to-json conversion table specifies that dict keys must be of a basic type: str, int, float, bool or None

However in practical usage, it's quite convenient to have objects as dictionary keys (especially, in lieu of data classes, leveraging the frozen=True option). Having the basic type restriction on keys makes encoding unnecessarily boilerplate-y.

Creating this issue for a potential coerce_keys kwarg to add to the public api. This gives the user the option of supplying a function to coerce non-basic type keys into a str.

[lidatong]

on reflection, this doesn't really seem like a compelling use-case