fix: broken link to sample app in README (#267)

Author: S-ecki

feedback/README.md

@@ -141,7 +141,7 @@ BetterFeedback.of(context).showAndUploadToSentry(
 | Firebase | [Firestore](https://pub.dev/packages/cloud_firestore), [Cloud Storage](https://pub.dev/packages/firebase_storage), [Database](https://pub.dev/packages/firebase_database)
 | Jira | Jira has a [REST API to create issues and upload files](https://developer.atlassian.com/server/jira/platform/jira-rest-api-examples/#creating-an-issue-examples) |
 | Trello | Trello has a [REST API to create issues and upload files](https://developer.atlassian.com/cloud/trello/rest/api-group-actions/) |
-| E-Mail | You can use the users email client like [in the sample app](https://github.com/ueman/feedback/blob/master/example/lib/main.dart) to send feedback to yourself using the [flutter_email_sender](https://pub.dev/packages/flutter_email_sender) plugin. |
+| E-Mail | You can use the users email client like [in the sample app](https://github.com/ueman/feedback/blob/master/feedback/example/lib/main.dart#L147-L160) to send feedback to yourself using the [flutter_email_sender](https://pub.dev/packages/flutter_email_sender) plugin. |
 
 If you have sample code on how to upload it to a platform, I would appreciate a pull request to the example app.