[native-assets] publish the first native-assets stable version 2.0.0

[rainyl]

Is your feature request related to a problem? Please describe.
Flutter 3.38 with dart 3.10 now support hooks (previously called native-assets), we can publish 2.x stable version now.

Additional context
This is a breaking change, 1.x will be frozen in current state and only fix critical bugs, we should warn this in README.