fix: log message when failing to create PR

lib/workers/pr/index.js

@@ -249,7 +249,7 @@ async function ensurePr(prConfig) {
         config.statusCheckVerify
       );
     } catch (err) {
-      logger.warn({ err }, `Failed to create PR`);
+      logger.warn({ err, message: err.message }, `Failed to create PR`);
       return null;
     }
     // Skip assign and review if automerging PR