Update phpstan/phpstan-phpunit requirement from 0.12.8 to 0.12.10

Updates the requirements on [phpstan/phpstan-phpunit](https://github.com/phpstan/phpstan-phpunit) to permit the latest version.
- [Release notes](https://github.com/phpstan/phpstan-phpunit/releases)
- [Commits](phpstan/phpstan-phpunit@0.12.8...0.12.10)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

composer.json

@@ -20,7 +20,7 @@
     "require-dev": {
         "doctrine/coding-standard": "^7.0",
         "phpstan/phpstan": "0.12.25",
-        "phpstan/phpstan-phpunit": "0.12.8",
+        "phpstan/phpstan-phpunit": "0.12.10",
         "phpstan/phpstan-strict-rules": "0.12.2",
         "phpunit/phpunit": "^8.5",
         "thecodingmachine/phpstan-safe-rule": "^1.0"