Use caret and adjust min version

[bruno-garcia]

Since we require Dart 2 or higher, we can use the caret notation to define dependency version requirements.

Whenever possible I used ^: https://dart.dev/tools/pub/dependencies#caret-syntax

Goal: Keep dependencies on the lowest possibly version to allow apps bump if/when they need and not because they've added sentry. Dev dependencies can be on the latest version:

Breaking http bumped to 0.12 for the nullability requirements

Dev dependencies bumped to the latest version.

uuid lowered to 2.0.0 (nothing on the changelog or in API compatibility says we need anything higher).

[bruno-garcia]

I'll merge this because the lock-file isnt' matching the pubspec.yaml anyway so main is broken:

  "runtimeInfo": {
  Unhandled exception:
    "panaVersion": "0.14.4",
  Exception: Running `flutter pub upgrade` failed with the following output:
    "sdkVersion": "2.10.1",
  

Bad state: For sentry, the parsed version null did not match the locked version 4.0.0.

#0      main (file:///app/bin/main.dart:74)
#1      _RootZone.runUnary (dart:async/zone.dart:1439)

https://github.com/getsentry/sentry-dart/pull/105/checks?check_run_id=1232406921

[bruno-garcia]

I'll open a follow up PR to address your feedback