Update phpstan/phpstan-strict-rules requirement from ^0.12.6 to ^0.12.9

Updates the requirements on [phpstan/phpstan-strict-rules](https://github.com/phpstan/phpstan-strict-rules) to permit the latest version.
- [Release notes](https://github.com/phpstan/phpstan-strict-rules/releases)
- [Commits](phpstan/phpstan-strict-rules@0.12.6...0.12.9)

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

composer.json

@@ -23,7 +23,7 @@
         "nette/tester": "^2.3.4",
         "mockery/mockery": "^1.4.2",
         "phpstan/phpstan": "^0.12.60",
-        "phpstan/phpstan-strict-rules": "^0.12.6",
+        "phpstan/phpstan-strict-rules": "^0.12.9",
         "pepakriz/phpstan-exception-rules": "^0.11.2",
         "nepada/phpstan-nette-tester": "^0.3.1",
         "spaze/phpstan-disallowed-calls": "^1.1",