[6.2] Remove mentions of v6.1 backers

Author: nicolas-grekas

README.md

@@ -3,19 +3,6 @@ Notifier Component
 
 The Notifier component sends notifications via one or more channels (email, SMS, ...).
 
-Sponsor
--------
-
-The Notifier component for Symfony 6.1 is [backed][1] by [Mercure.rocks][2].
-
-Create real-time experiences in minutes! Mercure.rocks provides a realtime API service
-that is tightly integrated with Symfony: create UIs that update in live with UX Turbo,
-send notifications with the Notifier component, expose async APIs with API Platform and
-create low level stuffs with the Mercure component. We maintain and scale the complex
-infrastructure for you!
-
-Help Symfony by [sponsoring][3] its development!
-
 Resources
 ---------
 
@@ -24,7 +11,3 @@ Resources
  * [Report issues](https://github.com/symfony/symfony/issues) and
    [send Pull Requests](https://github.com/symfony/symfony/pulls)
    in the [main Symfony repository](https://github.com/symfony/symfony)
-
-[1]: https://symfony.com/backers
-[2]: https://mercure.rocks
-[3]: https://symfony.com/sponsor