fix(steam): add referer and origin http headers to steam provider bec…

…ause of 403 Forbidden HTTP error (#1332)

Provider.php

@@ -234,6 +234,7 @@ public function getDefaultRequestOptions()
         return [
             RequestOptions::FORM_PARAMS => $this->getParams(),
             RequestOptions::PROXY       => $this->getConfig('proxy'),
+            RequestOptions::HEADERS     => $this->getHeaders(),
         ];
     }
 
@@ -271,6 +272,15 @@ public function getParams()
         return $params;
     }
 
+    public function getHeaders(): array
+    {
+        // Without it Steam returns 403 Forbidden
+        return [
+            'referer' => 'https://steamcommunity.com/',
+            'origin'  => 'https://steamcommunity.com',
+        ];
+    }
+
     /**
      * Parse openID response to an array.
      *