build(deps-dev): bump @vuepress/plugin-pwa from 1.0.0-alpha.0 to 1.8.2

Bumps [@vuepress/plugin-pwa](https://github.com/vuejs/vuepress/tree/HEAD/packages/@vuepress/plugin-pwa) from 1.0.0-alpha.0 to 1.8.2.
- [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/v1.8.2/packages/@vuepress/plugin-pwa)

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