[Workflow] Add bitExpert as a backer to the README

Author: nicolas-grekas

README.md

@@ -4,6 +4,22 @@ Workflow Component
 The Workflow component provides tools for managing a workflow or finite state
 machine.
 
+Sponsor
+-------
+
+The Workflow component for Symfony 6.2 is [backed][1] by [bitExpert][2].
+
+Their pulse is cross-technology software development that beats with every line of code.
+The basic principle for their solutions, products, and services is innovation, quality,
+commitment, and professionalism.
+
+bitExpert actively supports Open-Source and the software development community through various
+activities: Contributing to the Open-Source projects they love, organizing & hosting meetups,
+speaking at conferences, and organizing unKonf - an unconference focused on web
+and software development practices.
+
+Help Symfony by [sponsoring][3] its development!
+
 Resources
 ---------
 
@@ -12,3 +28,7 @@ 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://www.bitexpert.de
+[3]: https://symfony.com/sponsor