remove testing key

contrib/docker-compose/.env

@@ -36,7 +36,7 @@ DOCKER_APPLY_NEW_MIGRATIONS_AUTOMATICALLY="0"
 # Please do this before deploying an application!
 #
 # See: https://docs.pixelfed.org/technical-documentation/config/#app_key
-APP_KEY=base64:jL9zmd7/HBCssyNf9HpbuyqQB/KN/8Ew7A7GkogF1uc=
+APP_KEY=
 
 # See: https://docs.pixelfed.org/technical-documentation/config/#app_name-1
 APP_NAME="Pixelfed Prod"