Version: 3.1.2

Bug Description

The documentation says (https://doc.nette.org/en/application/bootstrap#toc-dynamic-parameters):

We can also add dynamic parameters to the container, their different values, unlike static parameters, will not cause the generation of new DI containers. Environment variables could be easily made available using dynamic parameters. We can access them via %env.variable% in configuration files.

When I try this in practice, the parameter value is null instead of the expected value of expanded env variable.

Steps To Reproduce

I created a minimal project that shows this problem: https://github.com/ondrejmirtes/nette-di-dynamic

The script test.php:

<?php

require_once __DIR__ . '/vendor/autoload.php';

$configurator = new Nette\Bootstrap\Configurator;
$configurator->setTempDirectory(__DIR__ . '/temp');
$configurator->addConfig(__DIR__ . '/test.neon');
$configurator->addDynamicParameters([
	'env' => getenv(),
]);
$container = $configurator->createContainer();

var_dump($container->parameters['test']);

The neon file test.neon:

parameters:
	test: %env.NETTE_TEST%/foo

How to run:

export NETTE_TEST=foo
php test.php

Expected Behavior

string(7) "foo/foo"

Actual Behaviour

NULL