feat(docs): add element-plus doc link

Author: wukd

.umirc.js

@@ -52,6 +52,10 @@ export default {
             title: '@formily/element',
             path: 'https://element.formilyjs.org',
           },
+          {
+            title: '@formily/element-plus',
+            path: 'https://element-plus.formilyjs.org',
+          },
           {
             title: '@formily/antdv',
             path: 'https://antdv.formilyjs.org',
@@ -151,6 +155,10 @@ export default {
             title: '@formily/element',
             path: 'https://element.formilyjs.org',
           },
+          {
+            title: '@formily/element-plus',
+            path: 'https://element-plus.formilyjs.org',
+          },
           {
             title: '@formily/antdv',
             path: 'https://antdv.formilyjs.org',