Merge pull request #185 from nlegoff/nlegoff/options-resolver-2.x

allow symfony/options-resolver:^2.6 as dependency

Author: dbu

composer.json

@@ -15,7 +15,7 @@
         "php-http/httplug": "^2.0",
         "php-http/message-factory": "^1.0",
         "php-http/message": "^1.6",
-        "symfony/options-resolver": " ^3.4.20 || ~4.0.15 || ~4.1.9 || ^4.2.1 || ^5.0"
+        "symfony/options-resolver": "^2.6 || ^3.4.20 || ~4.0.15 || ~4.1.9 || ^4.2.1 || ^5.0"
     },
     "require-dev": {
         "doctrine/instantiator": "^1.1",