Add Support For SharedPreferencesAsync and SharedPreferencesWithCache

[mcmah309]

shared_preferences in version 2.3, denoted SharedPreferences as a legacy api that will be deprecated in the future. The new suggested API's are SharedPreferencesAsync and SharedPreferencesWithCache. These should be supported as well.

[josh-burton]

I see this has been completed and merged, but not released to pub. @hoc081098 are you able to release an update please?

[hoc081098]

I see this has been completed and merged, but not released to pub. @hoc081098 are you able to release an update please?

Yes, I will draft a release