Use async API for Android 33+ (#195)

[lukehutch]

Fixes #195 (adds async API support for Android 33+) -- however I can't get the code to build on my machine, so I can't test it!

Pre-launch Checklist

• I made sure the project builds.
• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I updated pubspec.yaml with an appropriate new version according to the [pub versioning philosophy], or this PR is does not need version changes.
• I updated CHANGELOG.md to add a description of the change.
• I updated/added relevant documentation (doc comments with ///).
• I rebased onto main.
• I added new tests to check the change I am making, or this PR does not need tests.
• I made sure all existing and new tests are passing.
• I ran dart format . and committed any changes.
• I ran flutter analyze and fixed any errors.

[TimHoogstrate]

Dear @lukehutch,

Thanks for your input and help. We had some overlapping work while I was working on another issue. So i combined our work into a new PR PR 197 if you don't mind. I was able to test it on Android 29 and Android 34. Now it works as a charm.

Kind regards,

[lukehutch]

Awesome, thanks for this. Do you have a release planned sometime soon?

Actually I just noticed this rather heavy-handed decision by Google:

https://apilevels.com/

targetSdk must be 33+ for new apps and app updates since August 31, 2023.

Since even app updates require this, I believe this means that all support for API < 33 can simply be dropped. Is this a correct assumption?

[TimHoogstrate]

@lukehutch,

I think this is partly true because you it is also possible to ship an app outside of the play store. And then it might not de so strict. And it is also depending on the API level that the app is running on. If the app is for example running on API 29 it needs to work too.

Kind regards,

[lukehutch]

@TimHoogstrate Makes sense, I forgot there were other app stores :-)

What does your release schedule look like? Just trying to coordinate some things. Thanks!