Bump elliptic from 6.5.5 to 6.6.1 in /stackgl_modules

Bumps [elliptic](https://github.com/indutny/elliptic) from 6.5.5 to 6.6.1.
- [Commits](indutny/elliptic@v6.5.5...v6.6.1)

---
updated-dependencies:
- dependency-name: elliptic
  dependency-version: 6.6.1
  dependency-type: indirect
...

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

Author: dependabot[bot]