add types to api_internal extension info

ext/api_internal/info.php

@@ -11,9 +11,9 @@ class ApiInternalInfo extends ExtensionInfo
 {
     public const KEY = "api_internal";
 
-    public $key = self::KEY;
-    public $name = "Internal API";
-    public $authors = ["Daku"=>"admin@codeanimu.net", "Matthew Barbour"=>"matthew@darkholme.net"];
-    public $description = "Dependency extension used to provide a standardized source for performing operations via an API";
-    public $visibility = self::VISIBLE_HIDDEN;
+    public string $key = self::KEY;
+    public string $name = "Internal API";
+    public array $authors = ["Daku"=>"admin@codeanimu.net", "Matthew Barbour"=>"matthew@darkholme.net"];
+    public string $description = "Dependency extension used to provide a standardized source for performing operations via an API";
+    public string $visibility = self::VISIBLE_HIDDEN;
 }