minor symfony#61470 Bump phpunit-bridge to ^7.4|^8.0 (nicolas-grekas)

This PR was merged into the 6.4 branch.

Discussion
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 Bump phpunit-bridge to ^7.4|^8.0

| Q             | A
| ------------- | ---
| Branch?       | 6.4
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Issues        | -
| License       | MIT

Commits
-------

0388fdf 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",