Fix typo

src/Composer/IO/BaseIO.php

@@ -68,7 +68,7 @@ abstract class BaseIO implements IOInterface
                 if (!preg_match('{^[a-z0-9]+$}', $token)) {
                     throw new \UnexpectedValueException('Your github oauth token for '.$domain.' contains invalid characters: "'.$token.'"');
                 }
-                $io->setAuthentication($domain, $token, 'x-oauth-basic');
+                $this->setAuthentication($domain, $token, 'x-oauth-basic');
             }
         }
     }