Support 4.x dev branch

Author: muglug

composer.json

@@ -19,7 +19,7 @@
         "composer/semver": "^1.4 || ^2.0 || ^3.0",
         "composer/package-versions-deprecated": "^1.10",
         "phpunit/phpunit": "^7.5 || ^8.0 || ^9.0",
-        "vimeo/psalm": "^3.6.2 || dev-master"
+        "vimeo/psalm": "^3.6.2 || dev-master || dev-4.x"
     },
     "require-dev": {
         "codeception/codeception": "^4.0.3",