chore(deps): update vuepress monorepo

Author: renovate[bot]

package.json

@@ -5,8 +5,8 @@
     "now-build": "npm run docs:build && mv docs/.vuepress/dist dist"
   },
   "devDependencies": {
-    "@vuepress/plugin-pwa": "2.0.0-beta.48",
-    "vuepress": "2.0.0-beta.48"
+    "@vuepress/plugin-pwa": "2.0.0-rc.73",
+    "vuepress": "2.0.0-rc.19"
   },
   "name": "chemical-tools-page",
   "version": "1.0.0",