Improve composer.json syntax (#1008)

* Improve composer.json syntax

* Run composer upgrade with PHP 7.4

composer.json

@@ -30,7 +30,7 @@
 		"docs": "https://github.com/Froxlor/Froxlor/wiki"
 	},
 	"require": {
-		"php": ">=7.1",
+		"php": "^7.1 || ^8.0",
 		"ext-session": "*",
 		"ext-ctype": "*",
 		"ext-pdo": "*",
@@ -52,7 +52,6 @@
     },
 	"require-dev": {
 		"phpunit/phpunit": "^9",
-		"php": ">=7.3",
 		"ext-pcntl": "*",
 		"phpcompatibility/php-compatibility": "*",
 		"squizlabs/php_codesniffer": "*",