Update to Symfony 3.4 and make changes accordingly

Author: battye

.github/workflows/phpunit.yaml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php: ['7.0', '7.1', '7.2', '7.3', '7.4']
+        php: ['7.4']
 
     name: PHP ${{ matrix.php }} tests
     steps:

composer.json

@@ -20,19 +20,22 @@
 	],
 	"minimum-stability": "stable",
 	"require": {
-		"php": ">=5.5.9",
-		"symfony/yaml": "~3.0",
-		"symfony/console": "~3.0",
-		"symfony/finder": "~3.0",
+		"php": "~7.4",
+		"symfony/yaml": "~3.4",
+		"symfony/console": "~3.4",
+		"symfony/finder": "~3.4",
 		"battye/php-array-parser": "~1.0"
 	},
 	"require-dev": {
-		"phpunit/phpunit": "~5.7"
+		"phpunit/phpunit": "~9.0"
 	},
 	"bin": [
 		"translation.php"
 	],
 	"config": {
+		"platform": {
+			"php": "7.4.33"
+		},
 		"bin-dir": "bin"
 	},
 	"autoload": {