revert: build error due to 3rd-party API usage

Author: cxw620

docs/.vuepress/components/api/index.ts

@@ -1,5 +1,5 @@
 export const apis: Record<string, string> = {
-  cf: "https://api.example.com",
+  cf: "https://api.nn.ci",  // max 10, minutes 60, need further investigation
   cn: "https://api.xhofe.top",
   de: "http://api-my-api-5hw5ou-b810d8-80-75-218-107.traefik.me"
 };