Merge branch '5.4' into 6.0

* 5.4:
  [Cache] fix connecting to local Redis sockets
  Fix appveyor config for deprecations
  Skip deprecation coming from DBAL 3.2
  Add Suggestion class for more advanced completion suggestion
  [HttpClient] Add Klaxoon as a backer to the README
  [Translation] Add Lokalise as a backer to the READMEs
  [Translation] Add Crowdin as a backer to the READMEs
  [Security] Add SymfonyCasts as a backer to the READMEs
  [Notifier] Add Mercure.rocks as a backer to the README
  [Messenger][Process] Add SensioLabs as a backer to the README
  [HttpKernel][Console] Add Les-Tilleuls.coop as a backer to the README
  [HttpFoundation] Add Laravel as a backer to the README
  Allow v3 contracts where possible

Author: nicolas-grekas

README.md

@@ -3,6 +3,19 @@ Notifier Component
 
 The Notifier component sends notifications via one or more channels (email, SMS, ...).
 
+Sponsor
+-------
+
+The Notifier component for Symfony 5.4/6.0 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
 ---------
 
@@ -11,3 +24,7 @@ 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://mercure.rocks
+[3]: https://symfony.com/sponsor

composer.json

@@ -20,8 +20,8 @@
         "psr/log": "^1|^2|^3"
     },
     "require-dev": {
-        "symfony/event-dispatcher-contracts": "^2.0|^3.0",
-        "symfony/http-client-contracts": "^2.0|^3.0",
+        "symfony/event-dispatcher-contracts": "^2|^3",
+        "symfony/http-client-contracts": "^2|^3",
         "symfony/messenger": "^5.4|^6.0"
     },
     "conflict": {