Update phpunit/phpunit requirement from ^9.5.20 to ^9.5.21

Updates the requirements on [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) to permit the latest version. - [Release notes](https://github.com/sebastianbergmann/phpunit/releases) - [Changelog](https://github.com/sebastianbergmann/phpunit/blob/main/ChangeLog-9.5.md) - [Commits](sebastianbergmann/phpunit@9.5.20...9.5.21) --- updated-dependencies: - dependency-name: phpunit/phpunit dependency-type: direct:development ... Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

composer.json

@@ -39,7 +39,7 @@
  "mockery/mockery": "^1.5",
  "orchestra/testbench": "^6.28|^7.0",
  "orchestra/testbench-core": "^6.28|^7.0",
- "phpunit/phpunit": "^9.5.20"
+ "phpunit/phpunit": "^9.5.21"
  },
  "config": {
  "sort-packages": true