Fix retry delay

Author: remyleone

.markdownlinkcheck.json

@@ -24,6 +24,6 @@
   "timeout": "20s",
   "retryOn429": true,
   "retryCount": 5,
-  "fallbackRetryDelay": "30s",
+  "fallbackRetryDelay": "1s",
   "aliveStatusCodes": [200, 206, 429]
 }