Update vimeo/psalm requirement from ^2.0 to ^2.0 || ^3.0

Updates the requirements on [vimeo/psalm](https://github.com/vimeo/psalm) to permit the latest version.
- [Release notes](https://github.com/vimeo/psalm/releases)
- [Changelog](https://github.com/vimeo/psalm/blob/master/CHANGELOG.md)
- [Commits](vimeo/psalm@2.0.0...3.3.2)

composer.json

@@ -23,7 +23,7 @@
         "php-coveralls/php-coveralls": "^2.0",
         "phpstan/phpstan": "~0.9",
         "phpunit/phpunit": ">=6 <8",
-        "vimeo/psalm": "^2.0"
+        "vimeo/psalm": "^2.0 || ^3.0"
     },
     "config": {
         "sort-packages": true