Bump vuepress from 1.5.2 to 1.5.4 Bumps [vuepress](https://github.com/vuejs/vuepress/tree/HEAD/packages/vuepress) from 1.5.2 to 1.5.4. - [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/v1.5.4/packages/vuepress) Signed-off-by: dependabot-preview[bot]