Resolving dependencies...
The current Dart SDK version is 3.0.6.

Because expansion_card 0.1.0 doesn't support null safety and no versions of expansion_card match >0.1.0 <0.2.0, expansion_card ^0.1.0 is forbidden.
So, because flortnew depends on expansion_card ^0.1.0, version solving failed.

The lower bound of "sdk: '>=2.1.0 < 3.0.0'" must be 2.12.0 or higher to enable null safety.
For details, see https://dart.dev/null-safety