Bump sha.js from 2.4.11 to 2.4.12 in /flowauth/frontend

Bumps [sha.js](https://github.com/crypto-browserify/sha.js) from 2.4.11 to 2.4.12.
- [Changelog](https://github.com/browserify/sha.js/blob/master/CHANGELOG.md)
- [Commits](browserify/sha.js@v2.4.11...v2.4.12)

---
updated-dependencies:
- dependency-name: sha.js
  dependency-version: 2.4.12
  dependency-type: indirect
...

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

Author: dependabot[bot]