feature #1018 allow assigning role to organisation members (luceos)

This PR was squashed before being merged into the 3.4.x-dev branch.

Discussion
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This PR allows you to assign the `admin` role to new members of the organisation.

Ref: https://docs.github.com/en/rest/reference/orgs#set-organization-membership-for-a-user

Commits
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eb4e3c2 allow assigning roles to organisation members
480b919 remove default value and role check

Author: luceos

lib/Github/Api/Organization/Members.php

@@ -58,9 +58,9 @@ public function conceal($organization, $username)
     /*
      * Add user to organization
      */
-    public function add($organization, $username)
+    public function add($organization, $username, array $params = [])
     {
-        return $this->put('/orgs/'.rawurlencode($organization).'/memberships/'.rawurlencode($username));
+        return $this->put('/orgs/'.rawurlencode($organization).'/memberships/'.rawurlencode($username), $params);
     }
 
     public function addMember($organization, $username)