Relax guzzle package to version 6 in addition to version 7

Author: PWalkow

composer.json

@@ -13,26 +13,31 @@
         }
     ],
     "require": {
-        "php": ">=7.2",
+        "php": ">=7.4|^8.0",
         "ext-mbstring": "*",
         "ext-zlib": "*",
         "ext-curl": "*",
-        "paquettg/string-encode": "~1.0.0",
-        "php-http/httplug": "^2.1",
+        "paquettg/string-encode": "^1.0",
+        "php-http/httplug": "^2.0",
         "guzzlehttp/guzzle": "^7.0",
-        "guzzlehttp/psr7": "^1.6",
-        "myclabs/php-enum": "^1.7"
+        "guzzlehttp/psr7": "^2.0",
+        "myclabs/php-enum": "^1.8"
     },
     "require-dev": {
-        "phpunit/phpunit": "^7.5.1",
-        "mockery/mockery": "^1.2",
-        "infection/infection": "^0.13.4",
-        "phan/phan": "^2.4",
-        "friendsofphp/php-cs-fixer": "^2.16"
+        "phpunit/phpunit": "^9.0",
+        "mockery/mockery": "^1.0",
+        "infection/infection": "*",
+        "phan/phan": "^5.0",
+        "friendsofphp/php-cs-fixer": "^3.0"
     },
     "autoload": {
         "psr-4": { 
         	"PHPHtmlParser\\": "src/PHPHtmlParser"
        	}
+    },
+    "config": {
+        "allow-plugins": {
+            "infection/extension-installer": true
+        }
     }
 }