Bump elliptic from 6.5.4 to 6.5.7 in /docs

Bumps [elliptic](https://github.com/indutny/elliptic) from 6.5.4 to 6.5.7.
- [Commits](indutny/elliptic@v6.5.4...v6.5.7)

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

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