[Pitch] Allow coding of non-`String`/`Int` keyed `Dictionary` into a `KeyedContainer`

Evolution Pitches
17

Hi everybody!
Iā€™m inviting anyone that participated in this discussion thread to give their two cents on the proposal review thread:

https://forums.swift.org/t/se-0320-coding-of-non-string-int-keyed-dictionary-into-a-keyedcontainer/50903/6

Thanks! :pray: