Add attribution and the text of their license at the top of the file #96
Description
Example https://github.com/getsentry/sentry/blob/master/src/sentry/db/models/fields/jsonfield.py
### Tasks
- [x] https://github.com/getsentry/sentry-dart/pull/1351
- [x] https://github.com/getsentry/sentry-dart-plugin/pull/92
- [ ] https://github.com/getsentry/sentry-cocoa/issues/2844
- [ ] https://github.com/getsentry/sentry-fastlane-plugin/issues/193
- [ ] getsentry/sentry-java#2619
- [ ] getsentry/sentry-android-gradle-plugin#453
- [ ] https://github.com/getsentry/sentry-react-native/issues/2922