Merge branch '6.3' into 6.4

* 6.3:
  Fix symfony/deprecation-contracts require
  Remove 6.2 from the list of potential branch targets
  Bump Symfony version to 6.3.3
  Update VERSION for 6.3.2
  Update CHANGELOG for 6.3.2
  Bump Symfony version to 5.4.27
  Update VERSION for 5.4.26
  Update CONTRIBUTORS for 5.4.26
  Update CHANGELOG for 5.4.26
  Fix update slack messages documentation
  Fix symfony/deprecation-contracts require
  [Scheduler] Postpone schedule creation

Author: nicolas-grekas

composer.json

@@ -17,6 +17,7 @@
     ],
     "require": {
         "php": ">=8.1",
+        "symfony/deprecation-contracts": "^2.5|^3",
         "symfony/event-dispatcher-contracts": "^2.5|^3",
         "symfony/service-contracts": "^2.5|^3",
         "symfony/password-hasher": "^5.4|^6.0|^7.0"