chore: update readme (deprecations)

README.md

@@ -23,18 +23,10 @@ The `flutter build apk`, `flutter build ios` (or _macos_) or `flutter build web`
 
 ## Run
 
-### Dart
-
 ```bash
 dart run sentry_dart_plugin
 ```
 
-### Flutter
-
-```bash
-flutter packages pub run sentry_dart_plugin
-```
-
 ## Configuration (Optional)
 
 This tool comes with a default configuration. You can configure it to suit your needs.
@@ -69,7 +61,7 @@ in the format `--sentry-define=<KEY>=<VALUE>`. They take precedence over your fi
 but not over the alternative environment variables.
 
 ```bash
-flutter packages pub run sentry_dart_plugin --sentry-define=release=app-internal-test@0.0.1
+dart run sentry_dart_plugin --sentry-define=release=app-internal-test@0.0.1
 ```
 
 ### sentry.properties