OIDC Provider Configuration Response MUST return a JSON object (unless multiple values are returned)

According to the OIDC 1.0 Discovery specification
(https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderConfigurationResponse)

Section 4.2.  OpenID Provider Configuration Response
The response is a set of Claims about the OpenID Provider's configuration,
including all necessary endpoints and public key location information. A
successful response MUST use the 200 OK HTTP status code and return a JSON
object using the application/json content type that contains a set of Claims as
its members that are a subset of the Metadata values defined in Section 3. Other
Claims MAY also be returned.

Claims that return multiple values are represented as JSON arrays.
Claims with zero elements MUST be omitted from the response.

Author: selfsimilar

src/Model/Provider.php

@@ -79,8 +79,6 @@ public function __construct()
 
     public function toJson($options = 0)
     {
-        return json_encode([
-            $this->wellKnown
-        ], $options);
+        return json_encode($this->wellKnown, $options);
     }
 }