Update infection/infection requirement from ^0.26.16 to ^0.26.18 (#39)

Updates the requirements on [infection/infection](https://github.com/infection/infection) to permit the latest version.
- [Release notes](https://github.com/infection/infection/releases)
- [Changelog](https://github.com/infection/infection/blob/master/CHANGELOG.md)
- [Commits](infection/infection@0.26.16...0.26.18)

---
updated-dependencies:
- dependency-name: infection/infection
  dependency-type: direct:development
...

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composer.json

@@ -24,7 +24,7 @@
   },
   "require-dev": {
     "doctrine/coding-standard": "^11.1",
-    "infection/infection": "^0.26.16",
+    "infection/infection": "^0.26.18",
     "phpunit/phpunit": "^9.5.27",
     "psalm/plugin-phpunit": "^0.18.4",
     "vimeo/psalm": "^5.6"