[Security] Bump fstream in /angular/pipes/pure-impure

Bumps [fstream](https://github.com/npm/fstream) from 1.0.11 to 1.0.12. **This update includes a security fix.**
- [Release notes](https://github.com/npm/fstream/releases)
- [Commits](npm/fstream@v1.0.11...v1.0.12)

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

Author: dependabot-preview[bot]