Update "guzzlehttp/psr7": "^1.6" => "^2"

Author: Herberto Graca

composer.json

@@ -19,8 +19,8 @@
         "ext-curl": "*",
         "paquettg/string-encode": "~1.0.0",
         "php-http/httplug": "^2.1",
-        "guzzlehttp/guzzle": "^7.0",
-        "guzzlehttp/psr7": "^1.6",
+        "guzzlehttp/guzzle": "^7",
+        "guzzlehttp/psr7": "^2",
         "myclabs/php-enum": "^1.7"
     },
     "require-dev": {
@@ -31,8 +31,13 @@
         "friendsofphp/php-cs-fixer": "^2.16"
     },
     "autoload": {
-        "psr-4": { 
+        "psr-4": {
         	"PHPHtmlParser\\": "src/PHPHtmlParser"
        	}
+    },
+    "config": {
+        "allow-plugins": {
+            "ocramius/package-versions": true
+        }
     }
 }