Merge pull request #20 from weierophinney/feature/psalm-integration

Provide Psalm integration

Author: weierophinney

composer.json

@@ -39,7 +39,9 @@
     "require-dev": {
         "laminas/laminas-coding-standard": "~2.2.0",
         "phpspec/prophecy-phpunit": "^2.0",
-        "phpunit/phpunit": "^9.3"
+        "phpunit/phpunit": "^9.3",
+        "psalm/plugin-phpunit": "^0.16.0",
+        "vimeo/psalm": "^4.7"
     },
     "autoload": {
         "psr-4": {