Include MAIL_FROM_ADDR in phpunit configuration

.env.testing.example

@@ -17,5 +17,3 @@ DB_PORT=3306
 DB_DATABASE=null
 DB_USERNAME=null
 DB_PASSWORD=null
-
-MAIL_FROM_ADDR=you@example.com

phpunit.xml

@@ -21,6 +21,7 @@
     <env name="APP_ENV" value="testing"/>
     <env name="BCRYPT_ROUNDS" value="4"/>
     <env name="CACHE_DRIVER" value="array"/>
+    <env name="MAIL_FROM_ADDR" value="app@example.com"/>
     <env name="MAIL_MAILER" value="array"/>
     <env name="QUEUE_DRIVER" value="sync"/>
     <env name="SESSION_DRIVER" value="array"/>