Declare root, writer and properties members

Author: thekid

src/main/php/com/amazon/aws/lambda/Environment.class.php

@@ -12,6 +12,7 @@
  * @test  com.amazon.aws.lambda.unittest.EnvironmentTest
  */
 class Environment {
+  public $root, $writer, $properties;
 
   /** Creates a new environment */
   public function __construct(string $root, StringWriter $writer= null) {