Bump phpstan/phpstan from 0.12.3 to 0.12.9

Bumps [phpstan/phpstan](https://github.com/phpstan/phpstan) from 0.12.3 to 0.12.9.
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Commits](phpstan/phpstan@0.12.3...0.12.9)

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

Author: dependabot-preview[bot]

composer.json

@@ -4,7 +4,7 @@
     "type": "metapackage",
     "license": "MIT",
     "require": {
-        "phpstan/phpstan": "0.12.3",
+        "phpstan/phpstan": "0.12.9",
         "phpstan/phpstan-phpunit": "0.12.3",
         "phpstan/phpstan-mockery": "^0.12.3",
         "phpstan/phpstan-webmozart-assert": "0.12.1",