Update dependency psalm/plugin-phpunit to ^0.20.0

| datasource | package              | from   | to     |
| ---------- | -------------------- | ------ | ------ |
| packagist  | psalm/plugin-phpunit | 0.19.6 | 0.20.0 |

Author: renovate[bot]

composer.json

@@ -55,7 +55,7 @@
         "laminas/laminas-servicemanager": "^4.5.0",
         "php-http/curl-client": "^2.4.0",
         "phpunit/phpunit": "^11.5.52 || ^12.0.1 || ^13.0.1",
-        "psalm/plugin-phpunit": "^0.19.5",
+        "psalm/plugin-phpunit": "^0.20.0",
         "roave/security-advisories": "dev-master",
         "vimeo/psalm": "^6.15.1"
     },