Allow php-http/guzzle6-adapter 2.

Author: ekyna

README.md

@@ -21,6 +21,7 @@ $gateway = $factory->create([
     'site_id'     => '132456',
     'certificate' => '132456',
     'ctx_mode'    => Api::MODE_PRODUCTION,
+    'hash_mode'   => Api::HASH_MODE_SHA256,
     'directory'   => __DIR__ . '/payzen-cache',
 ]);
 

composer.json

@@ -22,7 +22,7 @@
     "require": {
         "php": "^7.1",
         "payum/core": "^1.5",
-        "php-http/guzzle6-adapter": "^1.1",
+        "php-http/guzzle6-adapter": "^1.1|^2.0",
         "symfony/options-resolver": "^3.0|^4.0|^5.0",
         "symfony/process": "^3.0|^4.0|^5.0",
         "psr/log": "^1.0"