fix(deps): update dependency vuepress-plugin-search-pro to v2.0.0-rc.21

Author: renovate[bot]

package.json

@@ -17,7 +17,7 @@
     "@vuepress/client": "2.0.0-rc.0",
     "vue": "^3.3.13",
     "vuepress": "2.0.0-rc.0",
-    "vuepress-plugin-search-pro": "2.0.0-rc.6",
+    "vuepress-plugin-search-pro": "2.0.0-rc.21",
     "vuepress-theme-hope": "2.0.0-rc.6"
   },
   "devDependencies": {