chore(deps-dev): bump @vuepress/plugin-pwa from 1.9.8 to 1.9.9 (#1023)

Bumps [@vuepress/plugin-pwa](https://github.com/vuejs/vuepress/tree/HEAD/packages/@vuepress/plugin-pwa) from 1.9.8 to 1.9.9.
- [Release notes](https://github.com/vuejs/vuepress/releases)
- [Changelog](https://github.com/vuejs/vuepress/blob/master/CHANGELOG.md)
- [Commits](https://github.com/vuejs/vuepress/commits/v1.9.9/packages/@vuepress/plugin-pwa)

---
updated-dependencies:
- dependency-name: "@vuepress/plugin-pwa"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -46,7 +46,7 @@
   "devDependencies": {
     "@vuepress/plugin-back-to-top": "1.9.9",
     "@vuepress/plugin-google-analytics": "1.9.9",
-    "@vuepress/plugin-pwa": "1.9.8",
+    "@vuepress/plugin-pwa": "1.9.9",
     "typescript": "4.9.5",
     "vuepress": "1.9.9"
   },