[composer] Set dependencies for 1.0.0-beta2 release

Author: Łukasz Serwatka

composer.json

@@ -5,7 +5,7 @@
     "type": "ezplatform-bundle",
     "require": {
         "php": "^7.3",
-        "ezsystems/ezpublish-kernel": "^8.0@dev",
+        "ezsystems/ezpublish-kernel": "^8.0",
         "symfony/dependency-injection": "^5.0",
         "symfony/http-kernel": "^5.0",
         "symfony/http-foundation": "^5.0",