Bump phpunit/phpunit from 8.3.1 to 8.3.3

Bumps [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) from 8.3.1 to 8.3.3.
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/master/ChangeLog-8.3.md)
- [Commits](sebastianbergmann/phpunit@8.3.1...8.3.3)

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

composer.json

@@ -26,7 +26,7 @@
     "phpstan/phpstan": "~0.11.12",
     "phpstan/phpstan-deprecation-rules": "~0.11.2",
     "phpstan/phpstan-strict-rules": "~0.11.1",
-    "phpunit/phpunit": "^8.3.1"
+    "phpunit/phpunit": "^8.3.3"
   },
   "config": {
     "preferred-install": "dist",