fix(deps): update dependency vuepress to v2.0.0-rc.18

Author: renovate[bot]

package.json

@@ -17,7 +17,7 @@
     "@waline/client": "3.3.2",
     "reveal.js": "5.1.0",
     "vue": "3.5.10",
-    "vuepress": "2.0.0-rc.9",
+    "vuepress": "2.0.0-rc.18",
     "vuepress-theme-hope": "2.0.0-rc.40"
   },
   "devDependencies": {