Bump fstream from 1.0.11 to 1.0.12 in /vue.demo/bitdemo

Bumps [fstream](https://github.com/npm/fstream) from 1.0.11 to 1.0.12.
- [Release notes](https://github.com/npm/fstream/releases)
- [Commits](https://github.com/npm/fstream/compare/v1.0.11...v1.0.12)
Signed-off-by: Ndependabot[bot] <support@github.com>