chore(deps-dev): bump @vuepress/plugin-back-to-top from 1.9.9 to 1.9.10

Bumps [@vuepress/plugin-back-to-top](https://github.com/vuejs/vuepress/tree/HEAD/packages/@vuepress/plugin-back-to-top) from 1.9.9 to 1.9.10.
- [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/v1.9.10/packages/@vuepress/plugin-back-to-top)

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

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -13,7 +13,7 @@
     "docker:build": "docker rm ttrss -f && docker-compose -f docker-compose.dev.yml up -d --build && docker logs ttrss -f"
   },
   "devDependencies": {
-    "@vuepress/plugin-back-to-top": "1.9.9",
+    "@vuepress/plugin-back-to-top": "1.9.10",
     "@vuepress/plugin-google-analytics": "1.9.10",
     "vuepress": "1.9.9"
   }