Support Flutter 2

[saharvx9]

Error:

Because firebase_auth >=1.0.0 depends on firebase_auth_web ^1.0.0 which depends on http_parser ^4.0.0, firebase_auth >=1.0.0 requires http_parser ^4.0.0.
And because firebase >=7.0.0 <9.0.0 depends on http_parser ^3.0.0, firebase_auth >=1.0.0 is incompatible with firebase >=7.0.0 <9.0.0.
And because firebase_analytics >=7.1.0 depends on firebase_analytics_web ^0.2.0 which depends on firebase ^7.3.0, firebase_auth >=1.0.0 is incompatible with firebase_analytics >=7.1.0.
So, because depends on both firebase_analytics ^7.1.0 and firebase_auth ^1.0.0, version solving failed.
pub get failed (1; So, because depends on both firebase_analytics ^7.1.0 and firebase_auth ^1.0.0, version solving failed.)