composer(deps-dev): Bump roave/backward-compatibility-check

Bumps [roave/backward-compatibility-check](https://github.com/Roave/BackwardCompatibilityCheck) from 8.4.0 to 8.6.0.
- [Release notes](https://github.com/Roave/BackwardCompatibilityCheck/releases)
- [Commits](Roave/BackwardCompatibilityCheck@8.4.0...8.6.0)

---
updated-dependencies:
- dependency-name: roave/backward-compatibility-check
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

composer.json

@@ -42,7 +42,7 @@
     "phpunit/phpunit": "^10.5.3",
     "psalm/plugin-phpunit": "~0.18.4",
     "rector/rector": "~0.18.12",
-    "roave/backward-compatibility-check": "^8.4.0",
+    "roave/backward-compatibility-check": "^8.6.0",
     "symfony/filesystem": "^6.4.0",
     "vimeo/psalm": "^5.18.0"
   },