Bump phpunit-bridge to ^7.4|^8.0

Author: nicolas-grekas

composer.json

@@ -155,7 +155,7 @@
         "psr/simple-cache": "^1.0|^2.0|^3.0",
         "seld/jsonlint": "^1.10",
         "symfony/mercure-bundle": "^0.3",
-        "symfony/phpunit-bridge": "^5.4|^6.0|^7.0",
+        "symfony/phpunit-bridge": "^7.4|^8.0",
         "symfony/runtime": "self.version",
         "symfony/security-acl": "~2.8|~3.0",
         "twig/cssinliner-extra": "^2.12|^3",