chore(deps): bump @vue/theme from 2.3.0 to 2.4.0

Bumps [@vue/theme](https://github.com/vuejs/theme) from 2.3.0 to 2.4.0.
- [Commits](vuejs/theme@v2.3.0...v2.4.0)

---
updated-dependencies:
- dependency-name: "@vue/theme"
  dependency-version: 2.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]