Update phpstan/phpstan-mockery requirement from ^0.12.11 to ^0.12.12

Updates the requirements on [phpstan/phpstan-mockery](https://github.com/phpstan/phpstan-mockery) to permit the latest version.
- [Release notes](https://github.com/phpstan/phpstan-mockery/releases)
- [Commits](phpstan/phpstan-mockery@0.12.11...0.12.12)

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

composer.json

@@ -28,7 +28,7 @@
         "phpstan/phpstan-nette": "^0.12.14",
         "nepada/phpstan-nette-tester": "^0.3.1",
         "spaze/phpstan-disallowed-calls": "^1.1",
-        "phpstan/phpstan-mockery": "^0.12.11",
+        "phpstan/phpstan-mockery": "^0.12.12",
         "php-parallel-lint/php-parallel-lint": "^1.2.0",
         "nepada/coding-standard": "^7.3"
     },