Move asdf-flutter to here

[oae]

I would like to pass maintainership of the asdf-flutter plugin to asdf-community.

[smorimoto]

Consult this discussion post: https://github.com/orgs/asdf-community/discussions/57 This is the smoothest way to go. Of course I can do all the work for you, but it's done on a best effort basis. (I've been busy with work lately...)

[NotHolst]

@oae I would like to nudge this.
If you want you can transfer the repo to me and i can handle the transfer process?

[ken-ty]

This repository has been migrated for my account.
I continue handle the transfer process.

[ken-ty]

asdf-community/infrastructure#141

[ken-ty]

asdf-community/infrastructure#157

[ken-ty]

Once asdf-community/infrastructure#157 is successfully merged, the migration is complete.

[ken-ty]

asdf-community/infrastructure#157 is successfully merged, thank you everyone!