Add union type to suppress deprecation warning

src/ClientInterface.php

@@ -19,7 +19,6 @@
 namespace Apigee\Edge;
 
 use Apigee\Edge\HttpClient\Utility\JournalInterface;
-use Http\Message\UriFactory;
 use Psr\Http\Client\ClientInterface as HttpClient;
 use Psr\Http\Message\ResponseInterface;
 
@@ -75,8 +74,12 @@ public function getJournal(): JournalInterface;
 
     /**
      * Returns the URI factory used by the Client.
+     *
+     * @return \Http\Message\UriFactory|\Psr\Http\Message\UriFactoryInterface
+     *
+     * @todo Restore native return type as \Psr\Http\Message\UriFactoryInterface in 4.0.0.
      */
-    public function getUriFactory(): UriFactory;
+    public function getUriFactory();
 
     /**
      * Returns the version of the API client.

src/HttpClient/Plugin/RetryOauthAuthenticationPlugin.php

@@ -20,8 +20,8 @@
 
 use Apigee\Edge\Exception\OauthAccessTokenAuthenticationException;
 use Apigee\Edge\HttpClient\Plugin\Authentication\AbstractOauth;
+use Exception;
 use Http\Client\Common\Plugin;
-use Http\Client\Exception;
 use Http\Promise\Promise;
 use Psr\Http\Message\RequestInterface;
 use Psr\Http\Message\ResponseInterface;
@@ -62,9 +62,8 @@ public function handleRequest(RequestInterface $request, callable $next, callabl
                 // Mark access token as expired and with that ensure that the authentication plugin gets a new
                 // access token.
                 $this->auth->getTokenStorage()->markExpired();
-                $promise = $first($request);
 
-                return $promise->wait();
+                return $first($request)->wait();
             }
 
             throw $exception;