chore(composer): add autoload-dev PSR-4 mapping for Tests namespace

Signed-off-by: Travis Garrison <travis@chiraqbookstore.com>

composer.json

@@ -57,6 +57,11 @@
             "**/Database/Migrations/**"
         ]
     },
+    "autoload-dev": {
+        "psr-4": {
+            "Tests\\": "tests/"
+        }
+    },
     "config": {
         "allow-plugins": {
             "phpstan/extension-installer": true