Add symfony 6 support (#19)

* Add symfony 6 compatibility, dropping 4

* Allow php:^8.1

* Add twig 3 compatibility, dropping 2

* Update unit tests

Author: janlam7

.github/workflows/main.yaml

@@ -8,7 +8,7 @@ jobs:
 
         strategy:
             matrix:
-                php-versions: ['7.3', '7.4', '8.0']
+                php-versions: ['8.1','8.2','8.3']
         name: PHP ${{ matrix.php-versions }}
         steps:
             -   uses: actions/checkout@v2

composer.json

@@ -16,19 +16,19 @@
         }
     ],
     "require": {
-        "php":                          "^7.3|^8.0",
-        "symfony/config":               "^4.2||^5.0",
-        "symfony/dependency-injection": "^4.2||^5.0",
-        "symfony/finder":               "^4.2||^5.0",
-        "symfony/framework-bundle":     "^4.2||^5.0",
-        "symfony/http-kernel":          "^4.2||^5.0"
+        "php":                          "^8.1",
+        "symfony/config":               "^5.4||^6.0",
+        "symfony/dependency-injection": "^5.4||^6.0",
+        "symfony/finder":               "^5.4||^6.0",
+        "symfony/framework-bundle":     "^5.4||^6.0",
+        "symfony/http-kernel":          "^5.4||^6.0"
     },
     "require-dev": {
         "phpspec/prophecy-phpunit": "^2.0",
         "phpunit/phpunit":          "^9.5.8",
-        "symfony/twig-bundle":      "^4.2||^5.0",
-        "symfony/yaml":             "^4.2||^5.0",
-        "twig/twig":                "^2.12.1"
+        "symfony/twig-bundle":      "^5.4||^6.0",
+        "symfony/yaml":             "^5.4||^6.0",
+        "twig/twig":                "^3.4.3"
     },
     "suggest": {
         "twig/twig": "Allows use of features in twig templates through the FeaturesExtension"

test/Functional/ConfigurationTest.php

@@ -18,7 +18,7 @@ protected function setUp(): void
 
     public function testFeatures(): void
     {
-        $container = static::$kernel->getContainer();
+        $container = self::getContainer();
         $features  = $container->get(FeatureContainer::class);
 
         // check if all the feature services are correcly configured
@@ -57,7 +57,7 @@ public function testFeatures(): void
 
     public function testTwigFeature(): void
     {
-        $container = static::$kernel->getContainer();
+        $container = self::getContainer();
 
         self::assertEquals(
             "feature is off",

test/Functional/Fixtures/config/config.yml

@@ -41,6 +41,7 @@ services:
 
 framework:
     secret: test
+    test: true
 
 twig:
     debug:            '%kernel.debug%'