make dependencies more flexible to avoid forcing the upgrade to dart 3.4.0

[insinfo]

make dependencies more flexible to avoid forcing the upgrade to dart 3.4.0

[pg_query] dart pub get --no-example
Resolving dependencies...
The current Dart SDK version is 3.2.1.

Because dartssh2 >=2.10.0 depends on pinenacl >=0.6.0 which requires SDK version >=3.4.0 <4.0.0, dartssh2 >=2.10.0 is forbidden.
So, because pg_query depends on dartssh2 ^2.10.0, version solving failed.


You can try one of the following suggestions to make the pubspec resolve:
* Try using the Dart SDK version: 3.5.3. See https://dart.dev/get-dart.