Remove the value of the APP_SECRET env var

Author: javiereguiluz

.env

@@ -16,7 +16,7 @@
 
 ###> symfony/framework-bundle ###
 APP_ENV=dev
-APP_SECRET=2ca64f8d83b9e89f5f19d672841d6bb8
+APP_SECRET=
 #TRUSTED_PROXIES=127.0.0.0/8,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16
 #TRUSTED_HOSTS='^(localhost|example\.com)$'
 ###< symfony/framework-bundle ###